[Allergic contact dermatitis caused by temporary black henna tattoos in two siblings].

Para-phenylenediamine (PPD) in black henna tattoo mixes is widely recognised as a cause of type-IV allergic contact dermatitis. Legislation in Western countries prohibits the use of PPD on the skin and limits the use in hairdye. In this report, we present a case of two brothers aged five and eight years with classical sensitization and illustrative contact dermatitis after repeatedly exposure to black henna. The hyper-sensitivity reaction to PPD was confirmed in later patch testing. The case serves as a reminder on the potential consequences of a seemingly harmless skin drawing.