Severe type IV hypersensitivity to 'black henna' tattoo.

A 16-year-old Bangladeshi girl presented with a 9-day history of an extensive pruritic, erythematous, papulovesicular skin eruption to both forearms. Appearance was 5 days following application of a home-made henna preparation. Examination revealed ulceration and scabbing along the whole henna pattern and early keloid formation. A diagnosis of type IV delayed hypersensitivity reaction superimposed by infection was initially made. As in this case, home-made henna preparations commonly combine commercial henna with black hair dye, paraphenylenediamine (PPD). PPD, widely known as 'black henna', darkens the pigment and precipitates the drying process. PPD is a potent contact allergen associated with a high incidence of hypersensitivity reactions. Despite treatment the patient was left with extensive keloid scarring in the pattern of the henna tattoo.