Temporary Henna Tattoos Can Cause Allergic Reactions, Permanent Scars

Getting a henna tattoo may earn a big reaction --- but not the kind a user was expecting.

The Federal Food and Drug Administration is warning users may have allergic reactions to so-called black henna, the dye used in temporary tattoos offered at tourist destinations and other specialty shops.

Henna is a reddish-brown pigment that comes from the flowering Lawsonia inermis plant, indigenous to tropical and subtropical regions of Africa and Asia. People have used natural henna as a cosmetic and a dye for hair and fabrics for thousands of years.

But the black henna is a different product altogether that actually might not include any natural henna at all. A key ingredient in that dye is p-phenylenediamine, or PPD, the same chemical used in hair coloring.

The allergic reactions to the PPD may include skin redness, blisters, oozing lesions, increased sensitivity to sunlight and even permanent scarring. Symptoms can occur right after a tattoo is applied to the surface of the skin or up to two or three weeks later, the FDA said.

A recent study in the Journal of the German Society of Dermatology indicated PPD was the key factor in seven cases of people who developed allergic reactions to hair and eyelash dyeing.

All the patients reported having negative reactions to PPD after receiving black henna tattoos.

It took about six years for the reaction to the hair dye to appear. The authors of the report added that PPD allergies could "have occupational impact, especially for hair dressers and cosmeticians."

Some states already have regulations in place for overseeing temporary tattoos, while others don't, the FDA noted.

The FDA asks anyone who believes they've suffered reactions to temporary tattoos or other cosmetics to contact MedWatch, the agency's safety information and reporting arm, or a regional consumer complaint coordinator.

The New Zealand Dermatological Society also maintains a Web page about PPD allergies.