Multiple macules, papules, nodules or plaques occur in a widespread distribution, particularly involving the trunk. The onset is usually between 1 and 9 months of age. The lesions erupt over several weeks, then become static and finally in most cases disappear over several years. The lesions are often significantly pigmented. They are usually pruritic and may blister. Urtication occurs and there may be dermographism in nearby clinically normal skin (Darier's sign). Generalized pruritus and flushing may occur, and less frequently other signs of mediator release.