[Persistent spontaneous erythema caused by topical use of fumaric acid monoethyl ester--an obligate mast cell degranulation?].

In 12 healthy volunteers the topical application of monoethyl fumarate caused a spontaneous persistent erythema. Systemic application induced flush. In urticaria pigmentosa the influence was significant higher than in normal skin. This fact suggests a mast cell degranulation caused by monoethyl fumarate.