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C078 Photopatch testing
Courses
-
European
Photodermatology
Group:
tolled. Saidman’s test is pathological in solar urticaria (typical wheals emerging immediately in the test sites), chronic actinic dermatitis (very low MED and eventually delayed eczematous secretion) and sometimes in polymorphous light eruption or lupus erythematosus (induction of specific lesions). The provocative phototesting is, in fact, the main step in the diagnosis; it establishes also the action spectrum and provides an objective way of monitoring efficacy of therapeutic measures. In all cases, a test site is repeatedly irradiated by both UVA and UVB and the phototest is deemed positive when the clinical pictures and histopathological features of experimental lesions are identical to the genuine sun-induced disease; contrarily, dose requirements, preferred test sites, time schedules for irradiations and reading vary in accordance with the photodermatosis suspected. The procedure today used to confirm polymorphic light-eruption, solar urticaria, hydroa vacciniform, solar prurigo, chronic actinic dermatitis and lupus erythematosus will be developed, in the speech. Of course, photopatchtesting and systemic phototest are here always negative, excepted in some CAD often without clinical pertinence. References
[l] HGlzle E. et col.: Photodermatology, 1987, 4: 109-l 14 [2] Beani J.C.: Ann. Dermatol. V&r&eol., 1987, 114, 1: 123-126 [3] Lehmann P. et col.: J. Am. Acad. Dermatol., 1990, 22: 181-7 I CO77 Investigation of photodermatoses R. Roelandts. University Hospital, Leuven, Belgium The investigation of a patient who does not tolerate sunlight should start with an extensive history because most patients consult after the lesions are disappeared and before they have new lesions. In several cases the diagnosis can already be made upon the history. In other cases such as solar urticaria chronic actinic dermatitis or actinic prurigo the patient history may be very suggestive but the diagnosis should be confirmed by phototesting. It can be important to test the patient with the right light source. In other patients it can be extremely difficult to make the diagnosis on a patient history or phototest result. These patients should return when they have lesions. Even then, additional investigations can be necessary before the final diagnosis can be made. This topic will discuss when biopsies are necessary, when and what blood samples have to be taken and which further investigations are necessary. I CO78 Photopatch testing E. Holzle. Department of Dermatology Oldenburg,
Oldenburg,
City
Hospital
Germany
The photopatch test is the procedure of choice for identification of phototoxic or photoallergic substances. The procedure has not been standardized internationally. Two groups, however, have proposed a standard protocol. These are the Scandinavian Photodermatitis Research Group and the German, Swiss and Austrian Photopatch Test Group. The latter adheres to the following method. The substances are applied to back skin via Finn -Chambers for 24 h. Test sites are irradiated with 10 J/cm2 UVA. Unirradiated controls are included. Test reactions are evaluated immediately after irradiation and on three successive
Photobiology
- Investigation
of Photodermatoses
Sl5
days. The grading system is based on morphological evaluation of the test reaction (+ = erythema, ++ = erythema and infiltration, +++ = erythema, infiltration, papulovesicles, ++++ = bullae or erosions). Test substances include disinfectans, sulfanilamide, promethazin-hydrochloride, chinidinsulphate, musk ambrette, fragrance mixture, and nine most widely used UVabsorbers. Analysing reaction patterns the distinction between phototoxic and photoallergic reactions is improved. In addition, clinical relevance of positive test reactions has to be evaluated carefully, since many non relevant phototoxic reactions may be observed. I CO79 Assessment of skin type H.C. Wulf. University of Copenhagen, Dept. of Dermatology, Bispebjerg
Hospital,
Copenhagen,
Denmark
Skin phototypes are here defined as the number of standard erythema doses (SED) that are needed to elicit just perceptible erythema on previously UV unexposed skin. In the majority of persons the test site may only be found on the buttocks. This measure is almost constant throughout the year and throughout life. The skin phototype is generally determined by a MED test. However, this test is insensitive for grading of UV sensitivity in fair-skinned Caucasians and the reproducibility is far less than generally expected. Other estimations of skin phototypes are built on questionnaires of anamnestic sun bum tendency and tanning ability and are easy to apply in population studies but are, however, unreliable. Other insensitive methods are built on race, includes eye colour and hair colour, or cards with colour of different grades of skin pigmentation. The best method is offered by skin reflectance measurements of pigmentation on unexposed buttock skin. Such measurement correlate well to MED phototest, have a high resolution in all races, are measures non-invasively, and may be performed in a few seconds.
CO80 UV measurements F.R. de Gruijl. Utrecht
Univ.,
Utrecht,
The Netherlands
In photodermatology UV dosimetry is often under-appreciated by the novice and dreaded by the experienced hand: if you are not careful, a physicist may come along and point out to you that what you wanted to measure is actually not what you thought you were measuring by reading your precious UV meter. Instead of concluding that this subject is then best left to the physicist, a modest effort to get acquainted with some basic principles will put you in the position to carry out your UV dosimetry correctly, e.g. by knowing the limitations of your hand-held UV meter, and by grasping the difference between exposure and fluence. In practice there are four prominent dimensions to UV irradiation and dosimetry: the wavelength (spectral composition and response), the geometry (angle, distance), time (aging, calibration), and costs. The first 3 are often poorly dealt with, and all too often a derivative of the last one.
-
European
Photodermatology
Group:
tolled. Saidman’s test is pathological in solar urticaria (typical wheals emerging immediately in the test sites), chronic actinic dermatitis (very low MED and eventually delayed eczematous secretion) and sometimes in polymorphous light eruption or lupus erythematosus (induction of specific lesions). The provocative phototesting is, in fact, the main step in the diagnosis; it establishes also the action spectrum and provides an objective way of monitoring efficacy of therapeutic measures. In all cases, a test site is repeatedly irradiated by both UVA and UVB and the phototest is deemed positive when the clinical pictures and histopathological features of experimental lesions are identical to the genuine sun-induced disease; contrarily, dose requirements, preferred test sites, time schedules for irradiations and reading vary in accordance with the photodermatosis suspected. The procedure today used to confirm polymorphic light-eruption, solar urticaria, hydroa vacciniform, solar prurigo, chronic actinic dermatitis and lupus erythematosus will be developed, in the speech. Of course, photopatchtesting and systemic phototest are here always negative, excepted in some CAD often without clinical pertinence. References
[l] HGlzle E. et col.: Photodermatology, 1987, 4: 109-l 14 [2] Beani J.C.: Ann. Dermatol. V&r&eol., 1987, 114, 1: 123-126 [3] Lehmann P. et col.: J. Am. Acad. Dermatol., 1990, 22: 181-7 I CO77 Investigation of photodermatoses R. Roelandts. University Hospital, Leuven, Belgium The investigation of a patient who does not tolerate sunlight should start with an extensive history because most patients consult after the lesions are disappeared and before they have new lesions. In several cases the diagnosis can already be made upon the history. In other cases such as solar urticaria chronic actinic dermatitis or actinic prurigo the patient history may be very suggestive but the diagnosis should be confirmed by phototesting. It can be important to test the patient with the right light source. In other patients it can be extremely difficult to make the diagnosis on a patient history or phototest result. These patients should return when they have lesions. Even then, additional investigations can be necessary before the final diagnosis can be made. This topic will discuss when biopsies are necessary, when and what blood samples have to be taken and which further investigations are necessary. I CO78 Photopatch testing E. Holzle. Department of Dermatology Oldenburg,
Oldenburg,
City
Hospital
Germany
The photopatch test is the procedure of choice for identification of phototoxic or photoallergic substances. The procedure has not been standardized internationally. Two groups, however, have proposed a standard protocol. These are the Scandinavian Photodermatitis Research Group and the German, Swiss and Austrian Photopatch Test Group. The latter adheres to the following method. The substances are applied to back skin via Finn -Chambers for 24 h. Test sites are irradiated with 10 J/cm2 UVA. Unirradiated controls are included. Test reactions are evaluated immediately after irradiation and on three successive
Photobiology
- Investigation
of Photodermatoses
Sl5
days. The grading system is based on morphological evaluation of the test reaction (+ = erythema, ++ = erythema and infiltration, +++ = erythema, infiltration, papulovesicles, ++++ = bullae or erosions). Test substances include disinfectans, sulfanilamide, promethazin-hydrochloride, chinidinsulphate, musk ambrette, fragrance mixture, and nine most widely used UVabsorbers. Analysing reaction patterns the distinction between phototoxic and photoallergic reactions is improved. In addition, clinical relevance of positive test reactions has to be evaluated carefully, since many non relevant phototoxic reactions may be observed. I CO79 Assessment of skin type H.C. Wulf. University of Copenhagen, Dept. of Dermatology, Bispebjerg
Hospital,
Copenhagen,
Denmark
Skin phototypes are here defined as the number of standard erythema doses (SED) that are needed to elicit just perceptible erythema on previously UV unexposed skin. In the majority of persons the test site may only be found on the buttocks. This measure is almost constant throughout the year and throughout life. The skin phototype is generally determined by a MED test. However, this test is insensitive for grading of UV sensitivity in fair-skinned Caucasians and the reproducibility is far less than generally expected. Other estimations of skin phototypes are built on questionnaires of anamnestic sun bum tendency and tanning ability and are easy to apply in population studies but are, however, unreliable. Other insensitive methods are built on race, includes eye colour and hair colour, or cards with colour of different grades of skin pigmentation. The best method is offered by skin reflectance measurements of pigmentation on unexposed buttock skin. Such measurement correlate well to MED phototest, have a high resolution in all races, are measures non-invasively, and may be performed in a few seconds.
CO80 UV measurements F.R. de Gruijl. Utrecht
Univ.,
Utrecht,
The Netherlands
In photodermatology UV dosimetry is often under-appreciated by the novice and dreaded by the experienced hand: if you are not careful, a physicist may come along and point out to you that what you wanted to measure is actually not what you thought you were measuring by reading your precious UV meter. Instead of concluding that this subject is then best left to the physicist, a modest effort to get acquainted with some basic principles will put you in the position to carry out your UV dosimetry correctly, e.g. by knowing the limitations of your hand-held UV meter, and by grasping the difference between exposure and fluence. In practice there are four prominent dimensions to UV irradiation and dosimetry: the wavelength (spectral composition and response), the geometry (angle, distance), time (aging, calibration), and costs. The first 3 are often poorly dealt with, and all too often a derivative of the last one.