Hypopigmentation after non-permanent henna tattoo

A young girl presented with a hypopigmentation in the shape of the sun. Dur ing a holiday in Egypt 3 months before a non-permanent henna tattoo had bee n 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-phen ylenediamine (PPD) but not to henna or any other standard allergen. Especia lly in Arabic countries PPD is a common additive in natural henna preparati ons to enhance the weak colouring properties of the natural henna dye. We c onclude that henna preparations may contain 'hidden' allergens, such as PPD , which can provoke severe cutaneous reaction without any cosensitization t o the henna dye itself.