Contact dermatitis from UV‐A and UV‐B filters in a patient with erythropoietic protoporphyria

The ROAT simulates the everyday use of dermatological or cosmetic products, so that a positive test means that the patient reacts to the test substance; however, it does not differentiate between allergic and cumulative irritant dermatitis. The size of the test area did not seem to affect the final result in these tests, although the response might be somewhat delayed if a very small area were used. From the practical point of view, it is difficult to perform the ROAT in an area as small as 1 x 1 em and using a very small amount of test substance. Therefore a test site of 5 x 5-10 x 10 em should be preferred. SHORT COMMUNICATIONS