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Amyopathic dermatomyositis (dermatomyositis siné myositis)
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Amyopathic dermatomyositis (dermatomyositis sin6 myositis) Presentation o f six new cases and review o f the literature Rebecca L. Euwer, MD, a and Richard D. Sontheimer, M D a, b Dallas, Texas We report six patients with the classic cutaneous findings of dermatomyositis who did not develop clinical or laboratory evidence of muscle disease for at least 2 years after onset of their skin manifestations. Such patients represent 11% of our total experience with dermatomyositis patients during a 15 year period. All six patients had Gottron's paules, periungual erythema/telangiectasia, and violaceous discoloration of the face, neck, upper chest, and back at some time during the course of their disease. In addition, all complained of pruritus and photosensitivity. None of the patients had evidence of malignancy. Each of five patients treated with oral corticosteroids for their cutaneous disease had marked improvement and did not develop myositis. These cases further emphasize that the cutaneous manifestations of dermatomyositis are pathognomonic of this disease and challenge the commonly held notion that muscle disease always develops within 2 years of onset of skin disease. (J AM ACAD DERMATOL 1991;24:959-66.) Polymyositis/dermatomyositis is classified as a connective tissue disorder with inflammation of the muscles that results in muscle weakness. When only muscle inflammation is involved, the term polymyosiris is used; when there is both muscle and skin inflammation, the disorder is referred to as dermatomyositis. It is not unusual for patients to present initially with only skin inflammation, the so-called "typical rash" of dermatomyositis, and then later develop muscle disease 3 to 6 months later. However, there is also a small group of patients who may never have muscle disease or in whom muscle involvement is minor and often transient. These patients have only skin inflammation as their primary manifestation of dermatomyositis, analogous to polymyositis patients who have only muscle inflammation. The inflammation of their skin-results in a cutaneous eruption that is clinically identical to that seen in more typical dermatomyositis patients. Der-
From the Departments of Dermatology a and Internal Medicine,b University of Texas Southwestern Medical Center. Presented at the Texas Dermatological Society meeting in San Antonio, Tex., May 14, 1988. Accepted for publication Feb. 6, 1991. Reprint requests: R. D. Sontheimer, MD, Department of Dermatology, LIT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 7 5235.
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matologists have acknowledged this entity as "dermatomyositis sin6 myositis" but we have been unable to find the origin of this term in the English-language literature. We propose the term arnyopathic dermatomyositis to describe patients with dermatomyosiris who primarily have skin disease and lack muscle involvement. Pearson 1 first suggested the term arnyopathic dermatomyositis in reference to several patients who had the classic cutaneous eruption of dermatomyositis with minimal to no muscle involvement. There has been no systematic review of patients with amyopathic dermatomyositis (dermatomyositis sin6 myositis). A literature search revealed only informal references to patients who exhibited only the cutaneous manifestations of dermatomyositis. 1-4 The reference most commonly cited, when amyopathic dermatomyositis or dermatomyositis sin6 myositis is referred to, is the report by Krain that describe six patients who had the classic skin changes of dermatomyositis without initial muscle involvement; however, all six patients ultimately developed muscle disease. 5 There is a reluctance to m a k e the diagnosis of derrnatomyositis only on the basis of the skin eruption because the typical the sine qua non for the diagnosis of dermatomyositis is muscle weakness. In fact, Bohan and Peter 6 have set forth criteria (Table I) that they propose must be present to make the di-
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Table I. Diagnostic criteria for dermatomyositis (DM)
1. Symmetric proximal muscle weakness with or without dysphagia or respiratory muscle involvement 2. Abnormal muscle biopsy specimen 3. Elevation of skeletal muscle-derived enzymes 4. Abnormal electromyogram 5. Typical skin rash
Confidence limits for diagnosis 1. Definite DM--rash and three or four criteria 2. Probable DM--rash and two criteria 3. Possible DM--rash and one criterion
Table II. Clinical characteristics Median time
(mo)betweenskin Mean age (yr)
Male: female
disease onset and diagn~is (range)
53.6
1:5
14 (5-24)
52.6
2:4
18 (2-50)
47.4
19:26
ND
Current study (n -- 6) Krain (n = 6) Bohan et al. (n = 45) ND, Not documented.
agnosis of dermatomyositis. On the basis of these criteria, the diagnosis of dermatomyositis cannot be made if only the cutaneous findings are present. However, we have seen several patients who have the classic cutaneous eruption of dermatomyositis but have not developed muscle involvement during at least the first 2 years of their disease. We believe the cutaneous eruption of dermatomyositis, when fully expressed, is pathognomonic of this disorder. Because of the paucity of published reviews and/or ease reports and the apparent controversy as to whether the diagnosis of dermatomyositis can be made only on the basis of cutaneous findings, we review our experience with six patients who have am3;opathic dermatomyositis. The objectives are to (1) examine and recognize common features of this group, (2) compare features of this group with published dermatomyositis series, and (3) review their course and treatment. MATERIAL AND METHODS
We reviewed the charts of patients with dermatomyositis seen in The University of Texas Southwestern Medical Center Outpatient Dermatology Department Clinic between the years 1973 and 1988. Patients were included in this review if they met the following criteria: (1) Pathognomonic clinical changes of cutaneous dermatomyositis: to be considered for the diagnosis of amyopathic dermatomyositis each patient had to have Gottron's papules as a minimal criterion. Lacking this, one patient had violaceous erythema of the knuckles without discrete papule formation in association with a periorbital heliotrope and was therefore included. (2) A skin biopsy specimen (with hematoxylin and eosin stain) compatible with dermatomyositis, (3) no clinical evidence of proximal motor weakness within 2 years of skin disease onset, and (4) normal muscle enzymes, creatine kinase (CK) and aldolase, within the first 2 years of illness.
RESULTS The prevalence of amyopathic dermatomyositis during a 15-year period at our institution was 11%; 6 of 54 patients met the aforementioned criteria for amyopathic dermatomyositis. In our study, the most common erroneous initial diagnoses made before referral to our clinic were (1) lupus erythematosus, (2) contact dermatitis, (3) lichen planus, (4) psoriasis, and (5) seborrheic dermatitis. The initial erroneous diagnoses in Krain's study 5 were (1) contact dermatitis, (2) polymorphous light eruption, (3) trichinosis, (4) atopic dermatitis, and (5) erythroderlFla.
Our patients had skin disease for a mean duration of 3.8 years (range 2 to 8 years). We have observed our patients for a mean period of 3 years. Most were seen after approximately 1 year of skin disease. In Krain's study, skin disease preceded the development of muscle disease by a mean period of 3 years (range 2 weeks to 6 years), Krain followed up his patients for a mean period of 8 years. The mean age in our study was 53.6 years (this figure does not include a 6-year-old child); in Krain's study the mean age was 52.6 years (also not including a single child). In the review of typical dermatomyositis patients by Bohan and Peter, 6 the mean age was 47.4 years (Table II). The male/female ratio in our study was 1:5; in Krain's study, 2:4, and in the review of Bohan and Peter, 19:26. The mean time in months between the, onset of skin disease and diagnosis of amyopathic dermatomyositis was 14 months in our study (range 5 to 24 months); in Krain's study, it was 18 months (range 2 to 50 months). This information was not available in Bohan and Peter's review of typical dermatomyositis patients. All patients in our series had moderate to severe pruritus; this was not documented in Krain's series.
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Table III. Characteristics of cutaneous involvement Current study I
(.=6) Alopecia Scalp inflammation Periorbital heliotrope Violaceous erythema of face Erythematous to violaceous macules or papules on: Bony prominences: IP joints Elbows Knees Shoulders Neck, chest, back Extensor arms Extensor legs Gottron's papules Periungual telangiectasia Periungual erythema Poikiloderma Violaceous erythema over extensor tendons
1/6 5/6 4/6 6/6
Krain
[ (n=6)
(17%) (83%) (67%) (100%)
ND ND 4/6 (67%) ND
(100%) (100%) (50%) (33%) (50%) (100%) (83%) (33%) (83%) (83%) 6/6 (100%) 2/6 (33%) 2/6 (33%)
ND 5/6 (83%) 5/6 (83%) 5/6 (83%) 3/6 (50%) 3/6 (50%) 5/6 (83%) 5/6 (83%) ND 4/6 (67%) ND 0 ND
6/6 6/6 3/6 2/6 3/6 6/6 5/6 2/6 5/6 5/6
IP. Interphalangeal; ND, not documented.
The location of the initial skin eruption was on the knuckles in two patients and on the face and upper trunk in the other four. No history of malignancy was obtained in our six patients and none in Krain's series. The most commonly associated symptom was photosensitivity, which occurred in all of our patients. Lethargy and fatigue were present in 50% of the patients; arthralgias occurred in one patient; one patient had carpal tunnel syndrome. In Krain's series, the most common symptoms were lethargy and fatigue; photosensitivity was second and arthralgias third. The cutaneous characteristics of the eruptions seen in our patients are presented in Table III. To summarize the cutaneous characteristics, all six patients had involvement of the face, involvement of the neck, chest, and back, involvement of the interphalangealjoints and periungual telangiectases and/ or erythema (Figs. 1, 2, and 3). Five of six patients (83%) also had scalp inflammation and one had nonscarring alopecia. Skin biopsy specimens from all patients were interpreted as consistent with dermatomyositis. The histopathologic characteristics seen most frequently were hyperkeratosis, basal keratinocyte liquefaction
Fig. 1. Gottron's papules and periungual telangiectasia.
degeneration, and a lymphohistiocytic perivascular inflammation. These are compared with the histopathologic characteristics seen in Krain's study in Table IV. Direct immunofluorescence was performed on five patients. One patients had a weak linear band of IgG and IgM. Two patients had subepidermal fluorescent cytoid bodies and two had negative direct immunofluorescence. Laboratory results are presented in Table V. A positive ANA (human HEp-2 cells as substrate) was found in half of our patients in contrast to Krain's series in which only one patient had a positive ANA. Speckled, diffuse, and homogeneous ANA patterns were seen. No patient had a positive anti--doublestranded DNA antibodies or precipitating antibodies to Ro/SS-A, La/SS-B, Sm, or U1RNP. An elevated erythrocyte sedimentation rate (ESR) was found in three of five, patients (60%). All patients in Krain's series, at some point in their course, had an elevated ESR. Muscle enzymes, specifically CK and aldolase, were normal in all our patients. In Krain's series, muscle enzymes were initially normal but all became abnormal. Treatment results are presented in Tables VI and VII. All five of the adult patients in our series were treated initially with high-dose prednisone (40 to 60 mg/day) for their symptomatic skin disease that had been present untreated for a mean duration of 14 months. In contrast, the patients in Krain's series were not treated with high-dose prednisone until the
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Fig. 2. Violaceous erythematous involvement of face, shoulders, chest, and dorsum of hands. Fig. 3. Poildlodermatous changes on the back.
onset of their muscle disease. In Krain's series, one pediatric patient received no treatment and had a spontaneous recovery. Another patient was treated with prednisone, 20 mg/day, for her skin disease and at the onset of muscle disease prednisone was increased to 40 mg/day. She had a good outcome at follow-up and exhibited no skin lesions or muscle weakness. Of the four patients in Krain's series who were treated with high-dose prednisone after the onset of muscle disease, two had residual muscle disease; one patient had residual muscle disease, pulmonary fibrosis, and skin disease; and one patient had residual pulmonary fibrosis at the time of follow-up. In our series, the pediatric patient was treated with hydroxychloroquine (Plaquenil) for 6 weeks, which did not improve her skin disease. After 3 years of skin disease, intermittent muscle pain has recently developed in her proximal thighs. Physical examination revealed normal strength but an electromyogram was abnormal. Two patients were treated with a combination of prednisone and hydroxychloroquine and they both improved significantly. However, at the time of follow-up, one patient had stopped her medications and was having a recurrence of her skin disease. Three patients were treated with prednisone alone and all these patients are currently without skin disease.
DISCUSSION Amyopathic dermatomyositis refers to a condition in which the typical cutaneous eruption of dermatomyositis is present but muscle disease is lacking. We have reviewed six patients with amyopathic dermatomyositis who have been without clinical or enzymatic evidence of muscle disease for at least 2 years. Although the numbers are too small to draw any firm conclusions, the female/male ratio in our series was higher than in typical dermatomyositis series. The average age was also older, if the pediatric patient is excluded. All patients had pruritus, which may help to distinguish them from patients with cutaneous lupus erythematosus who generally do not complain of severe itching. Arthralgias were uncommon, which is also true for patients with polymyositis/dermatomyositis. None of the patients in our series or in Krain's series developed or had an underlying malignancy. The combination of older age (greater than 40 years) and dermatomyositis as opposed to polymyositis has been said to increase the risk for underlying malignancy. Our results suggest that concurrent muscle disease might also be a risk factor. However, the number of patients in our series is too small to draw conclusions. Braverman 2 reported one woman with lung cancer who had only the cutaneous man-
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Table IV. Histopathologic characteristics
J Current study Hyperkeratosis Acanthosis Epidermal atrophy Papillomatoses Lymphocytic exocytosis Vacuolar alteration of basal keratinocytes Thickened basement membrane Homogenization of papillary dermis Melanin incontinence Colloid bodies Increased dermal mucin Increased dermal edema Lymphocytic infiltration of papillary dermis (perivascular) Follicular plugging
5/6 3/6 2/6 0 0 5/6
Table VI. Summary of treatment and outcome-current study Krain
(83%) 6/6 (I00%) (50%) ND (33%) 4/6 (66%) ND ND (83%) 1/6 (16%)
2/6 (33%) ND
Outcome
[
Hydroxyehloroquine Persistent skin disease, (1/6) abnormal EMG Prednisone and Minimal to no skin disease* hydroxychloroquine (one relapse after (2/6) discontinuation of therapy) Prednisone (3/6) All with minimal to no skin disease* *None of the patients have developed muscle disease.
1/6 (16%) ND 4/6 (66%) 2/6 (33%) 0 2/6 (33%) 6/6(100%)
ND ND ND 4/6 (66%) 6/6 (100%)
I/6 (16%) 6/6 (100%)
ND. Not documented.
Table V. Laboratory results Current, study
Positive ANA Positive Antinative DNA Anti-ENA Elevated ESR Muscle enzymes (CPK, aldo~ase)
Treatment
Krain
Table VII. Summary of treatment and outcome (Krain) Treatment
[
Outcome
None (1/6) Spontaneous recovery Prednisone, 20 mg, skin Good disease; prednisone, 40 mg at onset of muscle disease (1/6) High-dose prednisone Residual skin and muscle disease (2) (4/6) Residual muscle disease and pulmonary fibrosis
(1) Pulmonary fibrosis (1)
3/6 (50%)* 1/6 (16%) 0/6 (0) ND 0/6 (0) 3/5 (60%) Normal
ND 6/6 (100%) Initially normal, but all became abnormal
ENA, Extranuclear antigen; ND, not documented. *I-lep-2 substrate.
ifestations of dermatomyositis, and Bohan et al. 9 cited one patient with carcinoma of the uterus who had only skin findings but met other criteria for dermatomyositis; however, she lacked muscle weakness. The amyopathic dermatomyositis periorbital heliotrope discoloration is not as common as other cutaneous features. All six patients at some point during their course had ( I ) violaceous discoloration of interpbalangeal (joints and/or Gottron's papules, (2) periungual erythema and/or telangiectasia, and finally (3) violaceous discoloration of the face and upper trunk. It is our contention that these cutaneous findings are diagnostic for amyopathic der-
matomyositis when the skin biopsy specimen is consistent with dermatomyositis (Table VIII). The positive ANA found in half our patients as opposed to the findings in Krain's series, in which only one patient had a positive ANA, can probably be attributed our use of the more sensitive human Hep-2 tumor cell substrate, as opposed to the nonhuman substrates that were commonly used at the time of Krain's study. The cutaneous histopathologic features of dermatomyositis are not pathognomonic. However, there are certain histopathologic features that are compatible with the disorder, and those features were present in our patients' skin biopsy specimens.8 Immunofluorescent findings are also not specific and not helpful in making the diagnosis of dermatomyositis but may help rule out lupus erythematosus. It might be argued that had a more aggressive diagnostic approach been taken at the outset to identify clinically silent muscle disease in our patients (e.g., electromyograms, muscle biopsy) some of our amyopathic dermatomyositis patients would in fact have been found to have true dermatomyo-
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Amyopathic Dermatomyositis
Polymyositis
Dermatomyositis
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I I I
I [ I
Fig. 4. Clinical spectrum of polymyositis/dermatomyositis.
sitis. We did not believe these procedures were indicated because the results, either positive or negative, would not have influenced our treatment approach. In either case, we would have elected to treat with full doses of systemic corticosteroids because of the severity of the cutaneous symptoms. However, in any future prospective studies that address this issue, it would be important to correlate electromyographic and proximal muscle biopsy findings with cutaneous findings in patients early in their disease course. The amyopathic dermatomyositis patients were treated with high-dose corticosteroids primarily for their symptomatic skin disease. Specifically, five of six of our patients were treated with 40 to 60 mg prednisone daily. All patients responded within 4 to 6 weeks, and tapering of the prednisone was begun and adjusted on the basis of the clinical response. One year after starting prednisone, all patients were taking no more than half the original dose every day (two patients) or every other day (three patients). Hydroxychloroquine was added as a steroid-sparing agent in three patients. One patient had to discontinue this drug because of a cutaneous hypersensitivity reaction. Asof January 1988, one patient was taking prednisone, 10 mg every other day, and hydroxychloroquine, 200 mg twice a day; one patient was alternating 10 mg every other day with 7.5 mg every other day of prednisone; two have stopped prednisone with no other medication; and one was taking only hydroxychloroquine. All patients have none to minimal skin disease, except for the first patient who stopped all medications recently and developed a recurrence. This patient is the oldest in our
series and recently has developed glucose intolerance, presumably from the corticosteroids. None of our other patients had significant side effects from corticosteroids.Noneofourcorticosteroid-treatedpatients developed muscle disease as did all of Krain's patients eventually. His patients were not treated with corticosteroids for their skin disease. In his series a 72-year-old woman who was treated with corticosteroids for 4 years after onset of muscle disease, developed diabetes, osteoporosis, and cushingoid features. The comparison of our series with Krain's, although admittedly not a valid control group, suggests that our more aggressive approach to treating the skin disease may prevent the development of muscle disease in patients who initially have only skin involvement. Furthermore, early treatment with systemic corticosteroids may allow lower doses and shorter courses to control the disease, thereby resulting in fewer side effects. It should be emphasized that we would only treat a patient with amyopathic dermatomyositis for symptomatic skin disease in whom thebenefits appear to outweigh the risks. We believed the risk of corticosteroids in our pediatric patient with amyopathic dermatomyositis was not justified and hence this patient went untreated. The pediatric patient was the only one to ultimately develop signs and symptoms of muscle disease. There are major differences in the selection of our patients and in Kxain's series. In Krain's series, one patient presented initially with muscle weakness and skin disease, which spontaneously remitted, and then presented again with only skin disease and did not develop muscle disease for 6 years. Another two patients also presented early in their course with
Volume 24 Number 6, Part 1 June 1991
Table VIII. Cutaneous manifestations of dermatomyositis Pathognomonic 1. Gottron's papules 2. Gottron's sign---symmetric macular violaceous erythema with or without edema overlyingthe dorsal aspect of the ~nterphalangealjoints of the hands, oleeranon processes, patellas, and medial malleoli Characteristic 1. Periorbital violaceous erythema with associated edema of eyelids and periorbital tissue (heliotrope) 2. Periungual telangieetasia with associated dystrophic cuticles 3. Macular violaceous erythema overlyingthe dorsal aspect of hands, extensor forearms and arms, deltoids, posterior shoulders, nape of neck, V area of neck, upper chest, and forehead Compatible 1. Poikiloderma atrophieans vasculare (poikilodermatomyositis) 2. Subepidermal bullous lesions and superficial erosions Amyopathic dermatomyositis One or two pathognomonicsigns in associationwith one or more characteristic signs and a compatible skin biopsy specimen (hematoxylin-eosinstain)
muscle weakness, but because muscle enzymes, electromyography, and a biopsy specimen were normal, these patients were not treated. Hence, at least three of Krain's patients would not have met our inclusion criteria, specifically, lack of muscle disease for at least 2 years. The decision to use 2 years as a cutoff time was arbitrary although most investigators believe that the majority of patients with dermatomyositis who develop muscle disease do so within 2 years. Our group of patients challenges this commonly held notion. Furthermore, because they lacked muscle disease for such a prolonged period of time, there was considerable delay in diagnosis and considerable confusion regarding management. The diagnosis of amyopathic dermatomyositis need not be limited only to patients with skin disease for 2 years. Rather, any patient with only skin disease or with minimal muscle disease at presentation would warrant this diagnosis. Bohan et al. 9 reported that, in their series, on initial presentation, muscle strength was normal in 31% (48 patients). This emphasizes the importance of other clinical and laboratory features in early diagnosis. This agrees with other reports that approximately one third of the
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Table IX. Proposed revision of Bohan and Peter's original classification scheme Type
I II III IV V VI
I
Terms
Polymyositis Derrnatomyositis Myositis with malignancy Childhood myositis Myositis with other connective tissue disorders (overlap) Amyopathic dermatomyositis
cases initially have only cutaneous manifestations. Pearson 1~ acknowledged three cases of childhood derrnatomyositis, which he did not include in his series, with "very mild muscular weakness and more prominent.dermatologic features but relatively stable course over a 6-month to 3-year period." These patients were not treated with corticosteroids. He also reported five women with only the cutaneous manifestations of dermatomyositis; one for 13 years, and six others (four women and two men) in whom the eruption was florid, whereas weakness and electromyogram changes were minimal. 1 Bohan et al. 9 reported three patients (2%) in their series who failed to develop significant muscle weakness but met other diagnostic criteria (e.g., abnormal enzyme, EMG, or muscle biopsy. Don et al.11 reported a 26-year-old patient with a 13-year history of an erythematous patch on the chin. The patient had a 1-year-history of a periorbital heliotrope eruption and then a 4-month history of plaques on arms and thighs before developing muscle weakness. Randle and Winkelman lz reported a 4-year-old patient with skin findings of 2 years' duration with minimal but definite muscle weakness. Braverman 2 reported a 13-year-old patient with classic cutaneous changes without muscle disease for 10 years; and a 16-yearold patient with skin disease that spontaneously resolved after 2 years (a course of oral and topical steroids were tried unsuccessfully). From this discussion, it might be reasonable to divide amyopathic dermatomyositis patients into three types: Type 1 represents pure amyopathic dermatomyositis patients who have only skin disease. Type 2 are patients with skin disease who have subjective myalgias and weakness but no laboratory evidence of muscle disease (as seen in Krain's series). Type 3 are patients with no muscle weakness clinically but have evidence of abnormal laboratory tests
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at some time during their course. The unifying feature among these patients in their prominent skin disease and relative lack of muscle disease. If amyopathic dermatomyositis/dermatomyositis/polymyositis patients are grouped together, the disease can be viewed much like lupus erythematosus, as a spectrum or continuum with primary involvement of skin (amyopathic dermatomyositis) on one end and primary muscle involvement (polymyositis) at the other end, with a combination of the two (dermatomyositis) somewhere in the middle (Fig. 4). Currently, the majority of patients fall in the dermatomyositis/polymyositis portion of the spectrum; but with earlier aggressive treatment of the patients with amyopathic dermatomyositis who initially have only skin disease, there might be a decrease in patients who go on to develop significant muscle involvement. We suggest that the diagnostic criteria set forth by Bohan and Peter be altered to include criteria that would allow the diagnosis of amyopathic dermatomyositis to be made on the basis of the fully expressed cutaneous findings alone. Furthermore, we would include amyopathic dermatomyositis as a sixth type of dermatomyositis/polymyositis in the classification system proposed by Bohan et al. (Table IX).
Journal of the American Academy of Dermatology
REFERENCES 1. Pearson CM. Polymyositis and dermatomyositis. In: MeCatty D J, ed. Arthritis (and allied conditions). 9th ed. Philadelphia: Lea & Febiger, 1979:742. 2. Braverrnan I. Connective tissue (rheumatic) diseases. In: Cutaneous signs of systemic disease. 2nd ed. 1981:300-10. 3. Woo TY, Callen J, Voorhees J, et al. Cutaneous lesions of dermatomyositis are improved by hydroxychloroquine. J AM ACAD DERMATOL 1984;10:592-9. 4. Caro I. A dermatologist's view of dermatomyositis-polymyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:9-14. 5. Krain LS. Dermatomyositis in six patients without initial muscle involvement. Arch Dermatol 1975;3:241-5. 6. Bohan A, Peter .lB. Polymyositis and dermatomyositis. N Engl J Med 1975;292:344-7. 7. Callen JP. Malignancy in polymyositis/derrnatomyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:55-63. 8. Kasper CS, White CL, Freeman RG. Pathology and imrnunopathology of polymyositis/dermatomyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:64-76. 9. Bohan A, Peter JB, Bowman RL, et al. A computer-assisted analysis of 153 patients with polymyositis and dermatomyositis. Medicine 1977;56:255-86. 10. Pearson CM. Patterns of polymyositis and their response to treatment. Ann Intern Med 1976;59:827-38. 11. Don PC, Kahn T, Bickers D. Chloroquine-induced neutropenia in a patient with dermatomyositis. J AM ACAD DERMATOL 1987;16:629. 12. Randle HW, Winkelman RK. Steroid-induced acanthosis nigricans in dermatomyositis. Arch Dermatol 1979;155: 587-8.
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Amyopathic dermatomyositis (dermatomyositis sin6 myositis) Presentation o f six new cases and review o f the literature Rebecca L. Euwer, MD, a and Richard D. Sontheimer, M D a, b Dallas, Texas We report six patients with the classic cutaneous findings of dermatomyositis who did not develop clinical or laboratory evidence of muscle disease for at least 2 years after onset of their skin manifestations. Such patients represent 11% of our total experience with dermatomyositis patients during a 15 year period. All six patients had Gottron's paules, periungual erythema/telangiectasia, and violaceous discoloration of the face, neck, upper chest, and back at some time during the course of their disease. In addition, all complained of pruritus and photosensitivity. None of the patients had evidence of malignancy. Each of five patients treated with oral corticosteroids for their cutaneous disease had marked improvement and did not develop myositis. These cases further emphasize that the cutaneous manifestations of dermatomyositis are pathognomonic of this disease and challenge the commonly held notion that muscle disease always develops within 2 years of onset of skin disease. (J AM ACAD DERMATOL 1991;24:959-66.) Polymyositis/dermatomyositis is classified as a connective tissue disorder with inflammation of the muscles that results in muscle weakness. When only muscle inflammation is involved, the term polymyosiris is used; when there is both muscle and skin inflammation, the disorder is referred to as dermatomyositis. It is not unusual for patients to present initially with only skin inflammation, the so-called "typical rash" of dermatomyositis, and then later develop muscle disease 3 to 6 months later. However, there is also a small group of patients who may never have muscle disease or in whom muscle involvement is minor and often transient. These patients have only skin inflammation as their primary manifestation of dermatomyositis, analogous to polymyositis patients who have only muscle inflammation. The inflammation of their skin-results in a cutaneous eruption that is clinically identical to that seen in more typical dermatomyositis patients. Der-
From the Departments of Dermatology a and Internal Medicine,b University of Texas Southwestern Medical Center. Presented at the Texas Dermatological Society meeting in San Antonio, Tex., May 14, 1988. Accepted for publication Feb. 6, 1991. Reprint requests: R. D. Sontheimer, MD, Department of Dermatology, LIT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 7 5235.
1~/1/~s43
matologists have acknowledged this entity as "dermatomyositis sin6 myositis" but we have been unable to find the origin of this term in the English-language literature. We propose the term arnyopathic dermatomyositis to describe patients with dermatomyosiris who primarily have skin disease and lack muscle involvement. Pearson 1 first suggested the term arnyopathic dermatomyositis in reference to several patients who had the classic cutaneous eruption of dermatomyositis with minimal to no muscle involvement. There has been no systematic review of patients with amyopathic dermatomyositis (dermatomyositis sin6 myositis). A literature search revealed only informal references to patients who exhibited only the cutaneous manifestations of dermatomyositis. 1-4 The reference most commonly cited, when amyopathic dermatomyositis or dermatomyositis sin6 myositis is referred to, is the report by Krain that describe six patients who had the classic skin changes of dermatomyositis without initial muscle involvement; however, all six patients ultimately developed muscle disease. 5 There is a reluctance to m a k e the diagnosis of derrnatomyositis only on the basis of the skin eruption because the typical the sine qua non for the diagnosis of dermatomyositis is muscle weakness. In fact, Bohan and Peter 6 have set forth criteria (Table I) that they propose must be present to make the di-
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Table I. Diagnostic criteria for dermatomyositis (DM)
1. Symmetric proximal muscle weakness with or without dysphagia or respiratory muscle involvement 2. Abnormal muscle biopsy specimen 3. Elevation of skeletal muscle-derived enzymes 4. Abnormal electromyogram 5. Typical skin rash
Confidence limits for diagnosis 1. Definite DM--rash and three or four criteria 2. Probable DM--rash and two criteria 3. Possible DM--rash and one criterion
Table II. Clinical characteristics Median time
(mo)betweenskin Mean age (yr)
Male: female
disease onset and diagn~is (range)
53.6
1:5
14 (5-24)
52.6
2:4
18 (2-50)
47.4
19:26
ND
Current study (n -- 6) Krain (n = 6) Bohan et al. (n = 45) ND, Not documented.
agnosis of dermatomyositis. On the basis of these criteria, the diagnosis of dermatomyositis cannot be made if only the cutaneous findings are present. However, we have seen several patients who have the classic cutaneous eruption of dermatomyositis but have not developed muscle involvement during at least the first 2 years of their disease. We believe the cutaneous eruption of dermatomyositis, when fully expressed, is pathognomonic of this disorder. Because of the paucity of published reviews and/or ease reports and the apparent controversy as to whether the diagnosis of dermatomyositis can be made only on the basis of cutaneous findings, we review our experience with six patients who have am3;opathic dermatomyositis. The objectives are to (1) examine and recognize common features of this group, (2) compare features of this group with published dermatomyositis series, and (3) review their course and treatment. MATERIAL AND METHODS
We reviewed the charts of patients with dermatomyositis seen in The University of Texas Southwestern Medical Center Outpatient Dermatology Department Clinic between the years 1973 and 1988. Patients were included in this review if they met the following criteria: (1) Pathognomonic clinical changes of cutaneous dermatomyositis: to be considered for the diagnosis of amyopathic dermatomyositis each patient had to have Gottron's papules as a minimal criterion. Lacking this, one patient had violaceous erythema of the knuckles without discrete papule formation in association with a periorbital heliotrope and was therefore included. (2) A skin biopsy specimen (with hematoxylin and eosin stain) compatible with dermatomyositis, (3) no clinical evidence of proximal motor weakness within 2 years of skin disease onset, and (4) normal muscle enzymes, creatine kinase (CK) and aldolase, within the first 2 years of illness.
RESULTS The prevalence of amyopathic dermatomyositis during a 15-year period at our institution was 11%; 6 of 54 patients met the aforementioned criteria for amyopathic dermatomyositis. In our study, the most common erroneous initial diagnoses made before referral to our clinic were (1) lupus erythematosus, (2) contact dermatitis, (3) lichen planus, (4) psoriasis, and (5) seborrheic dermatitis. The initial erroneous diagnoses in Krain's study 5 were (1) contact dermatitis, (2) polymorphous light eruption, (3) trichinosis, (4) atopic dermatitis, and (5) erythroderlFla.
Our patients had skin disease for a mean duration of 3.8 years (range 2 to 8 years). We have observed our patients for a mean period of 3 years. Most were seen after approximately 1 year of skin disease. In Krain's study, skin disease preceded the development of muscle disease by a mean period of 3 years (range 2 weeks to 6 years), Krain followed up his patients for a mean period of 8 years. The mean age in our study was 53.6 years (this figure does not include a 6-year-old child); in Krain's study the mean age was 52.6 years (also not including a single child). In the review of typical dermatomyositis patients by Bohan and Peter, 6 the mean age was 47.4 years (Table II). The male/female ratio in our study was 1:5; in Krain's study, 2:4, and in the review of Bohan and Peter, 19:26. The mean time in months between the, onset of skin disease and diagnosis of amyopathic dermatomyositis was 14 months in our study (range 5 to 24 months); in Krain's study, it was 18 months (range 2 to 50 months). This information was not available in Bohan and Peter's review of typical dermatomyositis patients. All patients in our series had moderate to severe pruritus; this was not documented in Krain's series.
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Table III. Characteristics of cutaneous involvement Current study I
(.=6) Alopecia Scalp inflammation Periorbital heliotrope Violaceous erythema of face Erythematous to violaceous macules or papules on: Bony prominences: IP joints Elbows Knees Shoulders Neck, chest, back Extensor arms Extensor legs Gottron's papules Periungual telangiectasia Periungual erythema Poikiloderma Violaceous erythema over extensor tendons
1/6 5/6 4/6 6/6
Krain
[ (n=6)
(17%) (83%) (67%) (100%)
ND ND 4/6 (67%) ND
(100%) (100%) (50%) (33%) (50%) (100%) (83%) (33%) (83%) (83%) 6/6 (100%) 2/6 (33%) 2/6 (33%)
ND 5/6 (83%) 5/6 (83%) 5/6 (83%) 3/6 (50%) 3/6 (50%) 5/6 (83%) 5/6 (83%) ND 4/6 (67%) ND 0 ND
6/6 6/6 3/6 2/6 3/6 6/6 5/6 2/6 5/6 5/6
IP. Interphalangeal; ND, not documented.
The location of the initial skin eruption was on the knuckles in two patients and on the face and upper trunk in the other four. No history of malignancy was obtained in our six patients and none in Krain's series. The most commonly associated symptom was photosensitivity, which occurred in all of our patients. Lethargy and fatigue were present in 50% of the patients; arthralgias occurred in one patient; one patient had carpal tunnel syndrome. In Krain's series, the most common symptoms were lethargy and fatigue; photosensitivity was second and arthralgias third. The cutaneous characteristics of the eruptions seen in our patients are presented in Table III. To summarize the cutaneous characteristics, all six patients had involvement of the face, involvement of the neck, chest, and back, involvement of the interphalangealjoints and periungual telangiectases and/ or erythema (Figs. 1, 2, and 3). Five of six patients (83%) also had scalp inflammation and one had nonscarring alopecia. Skin biopsy specimens from all patients were interpreted as consistent with dermatomyositis. The histopathologic characteristics seen most frequently were hyperkeratosis, basal keratinocyte liquefaction
Fig. 1. Gottron's papules and periungual telangiectasia.
degeneration, and a lymphohistiocytic perivascular inflammation. These are compared with the histopathologic characteristics seen in Krain's study in Table IV. Direct immunofluorescence was performed on five patients. One patients had a weak linear band of IgG and IgM. Two patients had subepidermal fluorescent cytoid bodies and two had negative direct immunofluorescence. Laboratory results are presented in Table V. A positive ANA (human HEp-2 cells as substrate) was found in half of our patients in contrast to Krain's series in which only one patient had a positive ANA. Speckled, diffuse, and homogeneous ANA patterns were seen. No patient had a positive anti--doublestranded DNA antibodies or precipitating antibodies to Ro/SS-A, La/SS-B, Sm, or U1RNP. An elevated erythrocyte sedimentation rate (ESR) was found in three of five, patients (60%). All patients in Krain's series, at some point in their course, had an elevated ESR. Muscle enzymes, specifically CK and aldolase, were normal in all our patients. In Krain's series, muscle enzymes were initially normal but all became abnormal. Treatment results are presented in Tables VI and VII. All five of the adult patients in our series were treated initially with high-dose prednisone (40 to 60 mg/day) for their symptomatic skin disease that had been present untreated for a mean duration of 14 months. In contrast, the patients in Krain's series were not treated with high-dose prednisone until the
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Fig. 2. Violaceous erythematous involvement of face, shoulders, chest, and dorsum of hands. Fig. 3. Poildlodermatous changes on the back.
onset of their muscle disease. In Krain's series, one pediatric patient received no treatment and had a spontaneous recovery. Another patient was treated with prednisone, 20 mg/day, for her skin disease and at the onset of muscle disease prednisone was increased to 40 mg/day. She had a good outcome at follow-up and exhibited no skin lesions or muscle weakness. Of the four patients in Krain's series who were treated with high-dose prednisone after the onset of muscle disease, two had residual muscle disease; one patient had residual muscle disease, pulmonary fibrosis, and skin disease; and one patient had residual pulmonary fibrosis at the time of follow-up. In our series, the pediatric patient was treated with hydroxychloroquine (Plaquenil) for 6 weeks, which did not improve her skin disease. After 3 years of skin disease, intermittent muscle pain has recently developed in her proximal thighs. Physical examination revealed normal strength but an electromyogram was abnormal. Two patients were treated with a combination of prednisone and hydroxychloroquine and they both improved significantly. However, at the time of follow-up, one patient had stopped her medications and was having a recurrence of her skin disease. Three patients were treated with prednisone alone and all these patients are currently without skin disease.
DISCUSSION Amyopathic dermatomyositis refers to a condition in which the typical cutaneous eruption of dermatomyositis is present but muscle disease is lacking. We have reviewed six patients with amyopathic dermatomyositis who have been without clinical or enzymatic evidence of muscle disease for at least 2 years. Although the numbers are too small to draw any firm conclusions, the female/male ratio in our series was higher than in typical dermatomyositis series. The average age was also older, if the pediatric patient is excluded. All patients had pruritus, which may help to distinguish them from patients with cutaneous lupus erythematosus who generally do not complain of severe itching. Arthralgias were uncommon, which is also true for patients with polymyositis/dermatomyositis. None of the patients in our series or in Krain's series developed or had an underlying malignancy. The combination of older age (greater than 40 years) and dermatomyositis as opposed to polymyositis has been said to increase the risk for underlying malignancy. Our results suggest that concurrent muscle disease might also be a risk factor. However, the number of patients in our series is too small to draw conclusions. Braverman 2 reported one woman with lung cancer who had only the cutaneous man-
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Table IV. Histopathologic characteristics
J Current study Hyperkeratosis Acanthosis Epidermal atrophy Papillomatoses Lymphocytic exocytosis Vacuolar alteration of basal keratinocytes Thickened basement membrane Homogenization of papillary dermis Melanin incontinence Colloid bodies Increased dermal mucin Increased dermal edema Lymphocytic infiltration of papillary dermis (perivascular) Follicular plugging
5/6 3/6 2/6 0 0 5/6
Table VI. Summary of treatment and outcome-current study Krain
(83%) 6/6 (I00%) (50%) ND (33%) 4/6 (66%) ND ND (83%) 1/6 (16%)
2/6 (33%) ND
Outcome
[
Hydroxyehloroquine Persistent skin disease, (1/6) abnormal EMG Prednisone and Minimal to no skin disease* hydroxychloroquine (one relapse after (2/6) discontinuation of therapy) Prednisone (3/6) All with minimal to no skin disease* *None of the patients have developed muscle disease.
1/6 (16%) ND 4/6 (66%) 2/6 (33%) 0 2/6 (33%) 6/6(100%)
ND ND ND 4/6 (66%) 6/6 (100%)
I/6 (16%) 6/6 (100%)
ND. Not documented.
Table V. Laboratory results Current, study
Positive ANA Positive Antinative DNA Anti-ENA Elevated ESR Muscle enzymes (CPK, aldo~ase)
Treatment
Krain
Table VII. Summary of treatment and outcome (Krain) Treatment
[
Outcome
None (1/6) Spontaneous recovery Prednisone, 20 mg, skin Good disease; prednisone, 40 mg at onset of muscle disease (1/6) High-dose prednisone Residual skin and muscle disease (2) (4/6) Residual muscle disease and pulmonary fibrosis
(1) Pulmonary fibrosis (1)
3/6 (50%)* 1/6 (16%) 0/6 (0) ND 0/6 (0) 3/5 (60%) Normal
ND 6/6 (100%) Initially normal, but all became abnormal
ENA, Extranuclear antigen; ND, not documented. *I-lep-2 substrate.
ifestations of dermatomyositis, and Bohan et al. 9 cited one patient with carcinoma of the uterus who had only skin findings but met other criteria for dermatomyositis; however, she lacked muscle weakness. The amyopathic dermatomyositis periorbital heliotrope discoloration is not as common as other cutaneous features. All six patients at some point during their course had ( I ) violaceous discoloration of interpbalangeal (joints and/or Gottron's papules, (2) periungual erythema and/or telangiectasia, and finally (3) violaceous discoloration of the face and upper trunk. It is our contention that these cutaneous findings are diagnostic for amyopathic der-
matomyositis when the skin biopsy specimen is consistent with dermatomyositis (Table VIII). The positive ANA found in half our patients as opposed to the findings in Krain's series, in which only one patient had a positive ANA, can probably be attributed our use of the more sensitive human Hep-2 tumor cell substrate, as opposed to the nonhuman substrates that were commonly used at the time of Krain's study. The cutaneous histopathologic features of dermatomyositis are not pathognomonic. However, there are certain histopathologic features that are compatible with the disorder, and those features were present in our patients' skin biopsy specimens.8 Immunofluorescent findings are also not specific and not helpful in making the diagnosis of dermatomyositis but may help rule out lupus erythematosus. It might be argued that had a more aggressive diagnostic approach been taken at the outset to identify clinically silent muscle disease in our patients (e.g., electromyograms, muscle biopsy) some of our amyopathic dermatomyositis patients would in fact have been found to have true dermatomyo-
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Amyopathic Dermatomyositis
Polymyositis
Dermatomyositis
I I I
I I I
I [ I
Fig. 4. Clinical spectrum of polymyositis/dermatomyositis.
sitis. We did not believe these procedures were indicated because the results, either positive or negative, would not have influenced our treatment approach. In either case, we would have elected to treat with full doses of systemic corticosteroids because of the severity of the cutaneous symptoms. However, in any future prospective studies that address this issue, it would be important to correlate electromyographic and proximal muscle biopsy findings with cutaneous findings in patients early in their disease course. The amyopathic dermatomyositis patients were treated with high-dose corticosteroids primarily for their symptomatic skin disease. Specifically, five of six of our patients were treated with 40 to 60 mg prednisone daily. All patients responded within 4 to 6 weeks, and tapering of the prednisone was begun and adjusted on the basis of the clinical response. One year after starting prednisone, all patients were taking no more than half the original dose every day (two patients) or every other day (three patients). Hydroxychloroquine was added as a steroid-sparing agent in three patients. One patient had to discontinue this drug because of a cutaneous hypersensitivity reaction. Asof January 1988, one patient was taking prednisone, 10 mg every other day, and hydroxychloroquine, 200 mg twice a day; one patient was alternating 10 mg every other day with 7.5 mg every other day of prednisone; two have stopped prednisone with no other medication; and one was taking only hydroxychloroquine. All patients have none to minimal skin disease, except for the first patient who stopped all medications recently and developed a recurrence. This patient is the oldest in our
series and recently has developed glucose intolerance, presumably from the corticosteroids. None of our other patients had significant side effects from corticosteroids.Noneofourcorticosteroid-treatedpatients developed muscle disease as did all of Krain's patients eventually. His patients were not treated with corticosteroids for their skin disease. In his series a 72-year-old woman who was treated with corticosteroids for 4 years after onset of muscle disease, developed diabetes, osteoporosis, and cushingoid features. The comparison of our series with Krain's, although admittedly not a valid control group, suggests that our more aggressive approach to treating the skin disease may prevent the development of muscle disease in patients who initially have only skin involvement. Furthermore, early treatment with systemic corticosteroids may allow lower doses and shorter courses to control the disease, thereby resulting in fewer side effects. It should be emphasized that we would only treat a patient with amyopathic dermatomyositis for symptomatic skin disease in whom thebenefits appear to outweigh the risks. We believed the risk of corticosteroids in our pediatric patient with amyopathic dermatomyositis was not justified and hence this patient went untreated. The pediatric patient was the only one to ultimately develop signs and symptoms of muscle disease. There are major differences in the selection of our patients and in Kxain's series. In Krain's series, one patient presented initially with muscle weakness and skin disease, which spontaneously remitted, and then presented again with only skin disease and did not develop muscle disease for 6 years. Another two patients also presented early in their course with
Volume 24 Number 6, Part 1 June 1991
Table VIII. Cutaneous manifestations of dermatomyositis Pathognomonic 1. Gottron's papules 2. Gottron's sign---symmetric macular violaceous erythema with or without edema overlyingthe dorsal aspect of the ~nterphalangealjoints of the hands, oleeranon processes, patellas, and medial malleoli Characteristic 1. Periorbital violaceous erythema with associated edema of eyelids and periorbital tissue (heliotrope) 2. Periungual telangieetasia with associated dystrophic cuticles 3. Macular violaceous erythema overlyingthe dorsal aspect of hands, extensor forearms and arms, deltoids, posterior shoulders, nape of neck, V area of neck, upper chest, and forehead Compatible 1. Poikiloderma atrophieans vasculare (poikilodermatomyositis) 2. Subepidermal bullous lesions and superficial erosions Amyopathic dermatomyositis One or two pathognomonicsigns in associationwith one or more characteristic signs and a compatible skin biopsy specimen (hematoxylin-eosinstain)
muscle weakness, but because muscle enzymes, electromyography, and a biopsy specimen were normal, these patients were not treated. Hence, at least three of Krain's patients would not have met our inclusion criteria, specifically, lack of muscle disease for at least 2 years. The decision to use 2 years as a cutoff time was arbitrary although most investigators believe that the majority of patients with dermatomyositis who develop muscle disease do so within 2 years. Our group of patients challenges this commonly held notion. Furthermore, because they lacked muscle disease for such a prolonged period of time, there was considerable delay in diagnosis and considerable confusion regarding management. The diagnosis of amyopathic dermatomyositis need not be limited only to patients with skin disease for 2 years. Rather, any patient with only skin disease or with minimal muscle disease at presentation would warrant this diagnosis. Bohan et al. 9 reported that, in their series, on initial presentation, muscle strength was normal in 31% (48 patients). This emphasizes the importance of other clinical and laboratory features in early diagnosis. This agrees with other reports that approximately one third of the
Amyopathic dermatomyositis
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Table IX. Proposed revision of Bohan and Peter's original classification scheme Type
I II III IV V VI
I
Terms
Polymyositis Derrnatomyositis Myositis with malignancy Childhood myositis Myositis with other connective tissue disorders (overlap) Amyopathic dermatomyositis
cases initially have only cutaneous manifestations. Pearson 1~ acknowledged three cases of childhood derrnatomyositis, which he did not include in his series, with "very mild muscular weakness and more prominent.dermatologic features but relatively stable course over a 6-month to 3-year period." These patients were not treated with corticosteroids. He also reported five women with only the cutaneous manifestations of dermatomyositis; one for 13 years, and six others (four women and two men) in whom the eruption was florid, whereas weakness and electromyogram changes were minimal. 1 Bohan et al. 9 reported three patients (2%) in their series who failed to develop significant muscle weakness but met other diagnostic criteria (e.g., abnormal enzyme, EMG, or muscle biopsy. Don et al.11 reported a 26-year-old patient with a 13-year history of an erythematous patch on the chin. The patient had a 1-year-history of a periorbital heliotrope eruption and then a 4-month history of plaques on arms and thighs before developing muscle weakness. Randle and Winkelman lz reported a 4-year-old patient with skin findings of 2 years' duration with minimal but definite muscle weakness. Braverman 2 reported a 13-year-old patient with classic cutaneous changes without muscle disease for 10 years; and a 16-yearold patient with skin disease that spontaneously resolved after 2 years (a course of oral and topical steroids were tried unsuccessfully). From this discussion, it might be reasonable to divide amyopathic dermatomyositis patients into three types: Type 1 represents pure amyopathic dermatomyositis patients who have only skin disease. Type 2 are patients with skin disease who have subjective myalgias and weakness but no laboratory evidence of muscle disease (as seen in Krain's series). Type 3 are patients with no muscle weakness clinically but have evidence of abnormal laboratory tests
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at some time during their course. The unifying feature among these patients in their prominent skin disease and relative lack of muscle disease. If amyopathic dermatomyositis/dermatomyositis/polymyositis patients are grouped together, the disease can be viewed much like lupus erythematosus, as a spectrum or continuum with primary involvement of skin (amyopathic dermatomyositis) on one end and primary muscle involvement (polymyositis) at the other end, with a combination of the two (dermatomyositis) somewhere in the middle (Fig. 4). Currently, the majority of patients fall in the dermatomyositis/polymyositis portion of the spectrum; but with earlier aggressive treatment of the patients with amyopathic dermatomyositis who initially have only skin disease, there might be a decrease in patients who go on to develop significant muscle involvement. We suggest that the diagnostic criteria set forth by Bohan and Peter be altered to include criteria that would allow the diagnosis of amyopathic dermatomyositis to be made on the basis of the fully expressed cutaneous findings alone. Furthermore, we would include amyopathic dermatomyositis as a sixth type of dermatomyositis/polymyositis in the classification system proposed by Bohan et al. (Table IX).
Journal of the American Academy of Dermatology
REFERENCES 1. Pearson CM. Polymyositis and dermatomyositis. In: MeCatty D J, ed. Arthritis (and allied conditions). 9th ed. Philadelphia: Lea & Febiger, 1979:742. 2. Braverrnan I. Connective tissue (rheumatic) diseases. In: Cutaneous signs of systemic disease. 2nd ed. 1981:300-10. 3. Woo TY, Callen J, Voorhees J, et al. Cutaneous lesions of dermatomyositis are improved by hydroxychloroquine. J AM ACAD DERMATOL 1984;10:592-9. 4. Caro I. A dermatologist's view of dermatomyositis-polymyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:9-14. 5. Krain LS. Dermatomyositis in six patients without initial muscle involvement. Arch Dermatol 1975;3:241-5. 6. Bohan A, Peter .lB. Polymyositis and dermatomyositis. N Engl J Med 1975;292:344-7. 7. Callen JP. Malignancy in polymyositis/derrnatomyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:55-63. 8. Kasper CS, White CL, Freeman RG. Pathology and imrnunopathology of polymyositis/dermatomyositis. In: Sontheimer RD, ed. Polymyositis/dermatomyositis. Clin Dermatol 1988;6:64-76. 9. Bohan A, Peter JB, Bowman RL, et al. A computer-assisted analysis of 153 patients with polymyositis and dermatomyositis. Medicine 1977;56:255-86. 10. Pearson CM. Patterns of polymyositis and their response to treatment. Ann Intern Med 1976;59:827-38. 11. Don PC, Kahn T, Bickers D. Chloroquine-induced neutropenia in a patient with dermatomyositis. J AM ACAD DERMATOL 1987;16:629. 12. Randle HW, Winkelman RK. Steroid-induced acanthosis nigricans in dermatomyositis. Arch Dermatol 1979;155: 587-8.