Hypopigmentation after non-permanent henna tattoo.

A young girl presented with a hypopigmentation in the shape of the sun. During a holiday in Egypt 3 months before a non-permanent henna tattoo had been applied on her right upper arm. Three to 4 days later there was a severe cutaneous reaction followed by massive swelling of the arm. The lesion took 6 weeks to subside. Patch testing revealed positive reactions to para-phenylenediamine (PPD) but not to henna or any other standard allergen. Especially in Arabic countries PPD is a common additive in natural henna preparations to enhance the weak colouring properties of the natural henna dye. We conclude that henna preparations may contain 'hidden' allergens, such as PPD, which can provoke severe cutaneous reaction without any cosensitization to the henna dye itself.