- Email: [email protected]
The incidence of erythrasma of the toewebs
Letters [I] Peck SM, Rosenfeld H, Glick AW. Fungistatic power of blood serum. Arch Dermatol Syph 1940;42:426-437. [2] Kaaman T, Torssandcr J. Dcrmatophytid-a misdiagnosed entity? Acta Derm Venereol 1940;63:404-408. [3] Zaitz C, Proeqa NG. Dermatofitides. Estado atual dos conhecimentos. An Bras Dermatol 1990;65:265-267. [4] Soborg M. Bendixen G. Human lymphocyte migration as a parameter of hypersensitivity. Acta Med Stand 1967;181: 247-256.
The incidence of erythrasma
of the toewebs
To the Editor: Erythrasma is a mild chronic localized superficial infection of the skin [l-4] characterized by sharply delineated, dry, brown, slightly scaling patches occuring in the intertriginous areas, especially the axillae, the genitocrural crease, and the webs between the fourth and fifith toes and, less commonly, between the third and fourth toes [2]. Erythrasma is caused by infection with Coqmebacterium minutissimum [l-4]. In many cases, there is an associated tinea pedis [3] and it is exceedingly difficult to differentiate erythrasma of the toewebs from the mild tinea pedis [4]. Skin scrapings from between the fourth and fifth toewebs were macerated and examined in fixed Gram-stained smears for erythrasma [4], and KOH preparation for tinea pedis. Specimens were incubated at 35°C for 18-24 h [5] before culturing. The medium for fungal culture was Sabouraud’s Dextrose Agar. The study consisted of 200 patients of 68 (34%) females, and 132 (66%) males aged between 14 and 80. The KOH preparations revealed 162 (81%) positive scrapings for fungus. Gram stained preparations revealed 40 (20%) positive scrapings for erythrasma. A positive fungal culture was obtained from 82 (41%) for the 162 cases with a positive KOH examination. Bacteria grew on 36 (18%) aerobic cultures; they were examined microscopically afterwards and confirmed microbiologically. The most frequently isolated fungi were Trychophyton rubrum, Trychophyton mentagrophytes, and Epidermophyton floccosum, with rates of 82.3%, 14.7%, 3%, respectively. 28 patients had both erythrasma and fungi. All age groups may be affected, but erythrasma is much more frequent in adults than in children [3]. The incidence varies with the site of involvement; the toewebs are the most commonly affected with a reported incidence of 5% to 36% [l].
to the Editor [5] Zaitz C, Sadahiro A, Lirio VS et al. Preparation and evaluation of Trichophyton mentugrophytes antigens. Revista Iberoamericana de Micologia. Ref. No. 218.
* Corresponding author. 005 Szo Paulo, SP, Brazil.
Rua Tabapu?i,
1666, apt. 102, 04533-
SSDI 0926-9959(94)00010-O
In our series the frequency of erythrasma was 20%. There was a marked variation in sex difference (71% males, 29% females). In a study by Temple and associates [6], the frequency was 14.3% and most of the cases were males (17.5%). In a study by Serdaroglu and associates [7], the incidence of erythrasma of toewebs was 56%. In a study by Karaman and associates [s], the frequency was 23.7%. Somerville and associates [9] reported that 754 students examined for the first time, 144 (19%) were found to have erythrasma. In a study by Sarkany and associates [lo], the incidence of erythrasma was 22%. Few studies have reported an association with tinea pedis [3-71. In our study the frequency of tinea pedis was 81%. 14% of the cases had been associated with erythrasma. Serdaroglu and associates [7] reported that the frequency of fungal infections was 72%, and 40% of these cases were associated with erythrasma. Serap 6atiirkcan Bakici
Cumhuriyet [I]
* , A. Nevzat
University
Faculty
Yalqin,
Sibel Akinci,
of Medicine,
M. Zahir
Sivas, Turkey
McBridge ME, Duncan WC. Erythrasma. In: Clinical Dermatology. Demis DJ, Dahl MV, Smith EB, et al. (Eds.), 14th Edn., Philadelphia: Harper and Row Publ., 1987; Unit: 1632: l-6. [2] Arnold HL, Odom RB, James WD. Andrews’ diseases of the skin. Philadelphia: W.B. Saunders Co, 1990;284-285. [3] Duncan WC. Erythrasma and atrichomycosis axillaris. In: Infectious Diseases. Hoeprich PD, Jordan MC. (Eds.), 4th Edn., Philadelphia: JB Lippincott Company, 1989;10011004. [4] Swarts MN, Weinberg AN. Infections due to gram-positive bacteria. In: Dermatology in General Medicine. Fitzpatrick TB, Eisen AZ, Wolff K, et al. (Eds.), 3rd Edn., New York: McGraw-Hill Inc., 1987;2100-2121. 151Krech T, Hollis DG. Corynebacterium and related organisms. In: Manual of Clinical Microbiology. Balows A, Hausler WJ,
Letters
[6] [7]
[8] [9]
Herrmann KL, et al. (Eds.), 5th Edn., Washington: American Society for Microbiology 1992;277-286. Temple DE, Boardman CR. The incidence of erythrasma of the toewebs. Arch Dermatol 1962;86:518-519. Serdaroglu S, &imen A, &bayram H, Tcziin Y. Ayak parmak arasl enfeksiyonlannda wood q@mm tamsal degeri. Deri Hast Frengi Ar$ 1988;22:37-42. Karaman A. Hastanede yatan hastalarm ayagmda mikolojik Galqma. Deri hast Frengi Aq 1982;16:69-72. Somerville DA. Erythrasma in normal young adults. J Med Microbial 1970;3:57-64.
Diagnostic
accuracy
in cases of skin lesions
To the Editor: Methods for verifying the accuracy of clinical diagnosis are of primary importance for improvement of dermatologic knowledge. Until now, studies performed have considered only some types of lesions [1,2] but there is little or limited information about skin lesions as a whole. We have evaluated the accuracy of the clinical diagnosis in 3572 cases of skin lesions, the frequency of Correct and Incorrect diagnosis, in the attempt to detect criteria, if possible, for mistakes for different groups of skin lesions. The methods used were those reported by Lightstone [3], and diagnoses were divided into Correct positive (A): a clinically diagnosed lesion, histologically confirmed as the same; Incorrect positive (B): a lesion for which clinical diagnosis was not histologically confirmed; Incorrect negative CC): a lesion for which histological diagnosis was different from the clinical diagnosis. We evaluated the Diagnostic Accuracy = A X 100/A + B + C and the Index of Suspicion (Z,S) = Clinical Incidence (A + B) X lOO/Actual Incidence (A + C) in all cases.The 3572 skin lesionswere diagnosedby a stable staff of three specialists; only a single diagnosis, the most likely, was permitted. The clinical impression was verified by microscopic findings, the final diagnosis was based on the histopathology. The results are summarized in Table 1 with particular attention to the incorrect clinical diagnosesof somevery significant lesions. Any clinical diagnosis in dermatology may be difficult, but our own casesdemonstrate that some types of lesions are more difficult to diagnose than others. Our personal experience does not claim to represent the state of the art but only to provide
to the Editor [lo]
Sarkany I, Taplin D, Blank H. The etiology and treatment erythrasma. J Invest Dermatol 1961;37:283-288.
* Corresponding author. This paper was presented at the Third September 1993, Copenhagen, Denmark.
EADV
Congress,
of
26-30
SSDI 0926-9959(94)00016-X
somefurther information on this topic. The concepts of diagnostic accuracy (DA) and index of suspicion (IS) are useful but a more important aspect in the clinical diagnosis of skin lesions is the analysis of Incorrect diagnosis. Such analysis demonstratesthat histopathologic examination should not be dispensed with for all apparently easy to identify lesions. In fact, as well emphasized by Fiadero [4], the risks are overtreatment, under or ineffective treatment or fortuitous treatment. The concept of IS addressesthe question of underdiagnosisor over diagnosis.Some “easy” or not specific or “common” skin lesionscan give a great number of possibilities of misdiagnosiswith serious practical consequences.As Grin pointed out [2], it would be preferable, especially for a suspectedskin tumor, to have an overdiagnosis (IS > 100). Diagnostic skill is the fundamental basis for appropriate care in several dermatoses,especially in the preoperative phasein casesrequiring surgical therapy. Multiple variables interfere in the correct clinical diagnosis: the level of training of the physician, the nosological entity of the lesion in question, the possibly changing feature of a lesion. Recently Norman [5] stated that diagnostic errors are not predictable on the basis of stable characteristics or changing features of lesions. Thus, we think that further and more detailed studies on DA and related problems could lead to significant improvement in the diagnostic skill exercised in all departmentsof dermatology. R. Betti
* , E. Inselvini,
Clinica Dermatologica 20142 Milano, Italy
A. Lodi,
IV, Ospedale
C. Crosti
sari Paolo,
Via di Rudiini
8,
The incidence of erythrasma
of the toewebs
To the Editor: Erythrasma is a mild chronic localized superficial infection of the skin [l-4] characterized by sharply delineated, dry, brown, slightly scaling patches occuring in the intertriginous areas, especially the axillae, the genitocrural crease, and the webs between the fourth and fifith toes and, less commonly, between the third and fourth toes [2]. Erythrasma is caused by infection with Coqmebacterium minutissimum [l-4]. In many cases, there is an associated tinea pedis [3] and it is exceedingly difficult to differentiate erythrasma of the toewebs from the mild tinea pedis [4]. Skin scrapings from between the fourth and fifth toewebs were macerated and examined in fixed Gram-stained smears for erythrasma [4], and KOH preparation for tinea pedis. Specimens were incubated at 35°C for 18-24 h [5] before culturing. The medium for fungal culture was Sabouraud’s Dextrose Agar. The study consisted of 200 patients of 68 (34%) females, and 132 (66%) males aged between 14 and 80. The KOH preparations revealed 162 (81%) positive scrapings for fungus. Gram stained preparations revealed 40 (20%) positive scrapings for erythrasma. A positive fungal culture was obtained from 82 (41%) for the 162 cases with a positive KOH examination. Bacteria grew on 36 (18%) aerobic cultures; they were examined microscopically afterwards and confirmed microbiologically. The most frequently isolated fungi were Trychophyton rubrum, Trychophyton mentagrophytes, and Epidermophyton floccosum, with rates of 82.3%, 14.7%, 3%, respectively. 28 patients had both erythrasma and fungi. All age groups may be affected, but erythrasma is much more frequent in adults than in children [3]. The incidence varies with the site of involvement; the toewebs are the most commonly affected with a reported incidence of 5% to 36% [l].
to the Editor [5] Zaitz C, Sadahiro A, Lirio VS et al. Preparation and evaluation of Trichophyton mentugrophytes antigens. Revista Iberoamericana de Micologia. Ref. No. 218.
* Corresponding author. 005 Szo Paulo, SP, Brazil.
Rua Tabapu?i,
1666, apt. 102, 04533-
SSDI 0926-9959(94)00010-O
In our series the frequency of erythrasma was 20%. There was a marked variation in sex difference (71% males, 29% females). In a study by Temple and associates [6], the frequency was 14.3% and most of the cases were males (17.5%). In a study by Serdaroglu and associates [7], the incidence of erythrasma of toewebs was 56%. In a study by Karaman and associates [s], the frequency was 23.7%. Somerville and associates [9] reported that 754 students examined for the first time, 144 (19%) were found to have erythrasma. In a study by Sarkany and associates [lo], the incidence of erythrasma was 22%. Few studies have reported an association with tinea pedis [3-71. In our study the frequency of tinea pedis was 81%. 14% of the cases had been associated with erythrasma. Serdaroglu and associates [7] reported that the frequency of fungal infections was 72%, and 40% of these cases were associated with erythrasma. Serap 6atiirkcan Bakici
Cumhuriyet [I]
* , A. Nevzat
University
Faculty
Yalqin,
Sibel Akinci,
of Medicine,
M. Zahir
Sivas, Turkey
McBridge ME, Duncan WC. Erythrasma. In: Clinical Dermatology. Demis DJ, Dahl MV, Smith EB, et al. (Eds.), 14th Edn., Philadelphia: Harper and Row Publ., 1987; Unit: 1632: l-6. [2] Arnold HL, Odom RB, James WD. Andrews’ diseases of the skin. Philadelphia: W.B. Saunders Co, 1990;284-285. [3] Duncan WC. Erythrasma and atrichomycosis axillaris. In: Infectious Diseases. Hoeprich PD, Jordan MC. (Eds.), 4th Edn., Philadelphia: JB Lippincott Company, 1989;10011004. [4] Swarts MN, Weinberg AN. Infections due to gram-positive bacteria. In: Dermatology in General Medicine. Fitzpatrick TB, Eisen AZ, Wolff K, et al. (Eds.), 3rd Edn., New York: McGraw-Hill Inc., 1987;2100-2121. 151Krech T, Hollis DG. Corynebacterium and related organisms. In: Manual of Clinical Microbiology. Balows A, Hausler WJ,
Letters
[6] [7]
[8] [9]
Herrmann KL, et al. (Eds.), 5th Edn., Washington: American Society for Microbiology 1992;277-286. Temple DE, Boardman CR. The incidence of erythrasma of the toewebs. Arch Dermatol 1962;86:518-519. Serdaroglu S, &imen A, &bayram H, Tcziin Y. Ayak parmak arasl enfeksiyonlannda wood q@mm tamsal degeri. Deri Hast Frengi Ar$ 1988;22:37-42. Karaman A. Hastanede yatan hastalarm ayagmda mikolojik Galqma. Deri hast Frengi Aq 1982;16:69-72. Somerville DA. Erythrasma in normal young adults. J Med Microbial 1970;3:57-64.
Diagnostic
accuracy
in cases of skin lesions
To the Editor: Methods for verifying the accuracy of clinical diagnosis are of primary importance for improvement of dermatologic knowledge. Until now, studies performed have considered only some types of lesions [1,2] but there is little or limited information about skin lesions as a whole. We have evaluated the accuracy of the clinical diagnosis in 3572 cases of skin lesions, the frequency of Correct and Incorrect diagnosis, in the attempt to detect criteria, if possible, for mistakes for different groups of skin lesions. The methods used were those reported by Lightstone [3], and diagnoses were divided into Correct positive (A): a clinically diagnosed lesion, histologically confirmed as the same; Incorrect positive (B): a lesion for which clinical diagnosis was not histologically confirmed; Incorrect negative CC): a lesion for which histological diagnosis was different from the clinical diagnosis. We evaluated the Diagnostic Accuracy = A X 100/A + B + C and the Index of Suspicion (Z,S) = Clinical Incidence (A + B) X lOO/Actual Incidence (A + C) in all cases.The 3572 skin lesionswere diagnosedby a stable staff of three specialists; only a single diagnosis, the most likely, was permitted. The clinical impression was verified by microscopic findings, the final diagnosis was based on the histopathology. The results are summarized in Table 1 with particular attention to the incorrect clinical diagnosesof somevery significant lesions. Any clinical diagnosis in dermatology may be difficult, but our own casesdemonstrate that some types of lesions are more difficult to diagnose than others. Our personal experience does not claim to represent the state of the art but only to provide
to the Editor [lo]
Sarkany I, Taplin D, Blank H. The etiology and treatment erythrasma. J Invest Dermatol 1961;37:283-288.
* Corresponding author. This paper was presented at the Third September 1993, Copenhagen, Denmark.
EADV
Congress,
of
26-30
SSDI 0926-9959(94)00016-X
somefurther information on this topic. The concepts of diagnostic accuracy (DA) and index of suspicion (IS) are useful but a more important aspect in the clinical diagnosis of skin lesions is the analysis of Incorrect diagnosis. Such analysis demonstratesthat histopathologic examination should not be dispensed with for all apparently easy to identify lesions. In fact, as well emphasized by Fiadero [4], the risks are overtreatment, under or ineffective treatment or fortuitous treatment. The concept of IS addressesthe question of underdiagnosisor over diagnosis.Some “easy” or not specific or “common” skin lesionscan give a great number of possibilities of misdiagnosiswith serious practical consequences.As Grin pointed out [2], it would be preferable, especially for a suspectedskin tumor, to have an overdiagnosis (IS > 100). Diagnostic skill is the fundamental basis for appropriate care in several dermatoses,especially in the preoperative phasein casesrequiring surgical therapy. Multiple variables interfere in the correct clinical diagnosis: the level of training of the physician, the nosological entity of the lesion in question, the possibly changing feature of a lesion. Recently Norman [5] stated that diagnostic errors are not predictable on the basis of stable characteristics or changing features of lesions. Thus, we think that further and more detailed studies on DA and related problems could lead to significant improvement in the diagnostic skill exercised in all departmentsof dermatology. R. Betti
* , E. Inselvini,
Clinica Dermatologica 20142 Milano, Italy
A. Lodi,
IV, Ospedale
C. Crosti
sari Paolo,
Via di Rudiini
8,