[Allergic contact eczema to a long-used cosmetic: Methylisothiazolinon, a type IV-allergen].

Methylisothiazolinone was permitted in 2004 as preservative in rinse-off and leave-on products by the European cosmetics directive. This led to a dramatic increase in contact eczemas induced by MI in the past few years. Here, we report a patient who developed a spreading contact eczema of the face, neck and proximal arms mimicking a photodermatosis. The reaction was caused by use of a facial ointment that only recently started to contain MI. Type IV-sensitization to MI was verified by patch testing.