Because henna tattoos are temporary and quick to apply, many believe they are a harmless alternative to permanent tattoos.

Parents, however, should be cautious before allowing their children to get henna tattoos. While natural henna is safe, it commonly is mixed with para-phenylenediamine (PPD), a chemical used to make the tattoos dark black, more closely resemble real tattoos and dry faster.

“The problem with PPD is that it is a frequent contact sensitizer,” said Albert Yan, M.D., FAAP, a member of the Section on Dermatology of the American Academy of Pediatrics. Allergic contact sensitizers can cause reactions ranging from itchy skin to blisters and scarring.

Although a person may not experience a negative reaction after the first contact with PPD, that first exposure can cause the body to become sensitive to PPD. Once a person is sensitized, only a small amount of the chemical can provoke a very strong reaction.

“Not everybody will become sensitized, but repeated exposure increases the risk,” Dr. Yan said. “Once a person is sensitized to PPD, he or she also can be cross-sensitized to similar chemicals like sulfonamides, a common component of antibiotics. This is pretty common, and there have been hundreds of reported cases now.”

The following can help parents determine if henna paste contains PPD:

  • Natural henna is a greenish khaki color. If the henna paste appears jet black, it most likely contains PPD.

  • Ask how long the paste needs to be left on. Natural henna takes several hours to dry and flake off and never works in less than one hour.

  • Ask what color the tattoo will be once the paste comes off. If it is black, there is PPD in the henna. Henna will leave an orange stain that will darken to red brown or dark brown but not black.

©2009 American Academy of Pediatrics. This information may be freely copied and distributed with proper attribution.