[Possible aggravation of a Henoch Schoenlein purpura by isotretinoin].

We report on a 16 year old patient with a hemorrhagic bullous form of a Henoch-Schönlein purpura. The cause for the event could not be determined, but the patient recovered without complications. Since he had begun a therapy with isotretinoin due to an acne inversa 3 weeks before, a possible association between the event and the treatment could not be excluded, and the case was reported to Swissmedic. In the comment, we discuss the pharmacology of isotretinoin, drug-induced vasculitis, and its pathomechanisms. As a general reminder, the criteria for the causality assessment of adverse drug reactions as well as the reporting system of adverse drug reactions in Switzerland are discussed.