Diagnosis: Contact Dermatitis to Paraphenylenediamine

The patient’s mother reported blisters, erythema, and scabbing in the area of the tattoo. Six months later, the patient underwent paraphenylenediamine patch testing and exhibited a reaction.

The patient was treated with mild topical steroids and a 4-day prednisone course prior to presentation. A week of clobetasol ointment improved the pruritus and erythema.

Henna is a green powdered extract derived from the leaves of the Lawsonia alba plant. The active ingredient is lawsone. Middle Eastern and Indian cultures use the extract to dye the hair, skin, and nails. Contact with the skin for an extended period of time yields a brownish orange pigment. In Western countries, Henna tattoos have gained popularity as a temporary alternative to ink tattoos.

Henna may be used in its pure form, however, paraphenylenediamine (PPD) is often added to darken the pigment, expedite drying time, and improve design accuracy. PPD is an allergen found in hair dyes and photographic film processing. It is a potent T-cell stimulator, and its efficacy is directly related to concentration and duration of exposure. Patch tests among individuals with henna contact dermatitis are negative to pure henna powder but react strongly to PPD, which has lead to the assumption that PPD is the main allergen in henna paste.

Henna tattoo inks have been found to have PPD concentrations as high as 15%-30%, and, often, the inks are in contact with the skin for several days after application. The hypersensitivity can sensitize individuals to PPD-containing substances such as dark hair dyes and dark clothing. Cross reaction may cause hypersensitivity to natural rubber latex, azo dyes, thiurams, PABA sunscreen, para-aminosalicylic acid, and benzocaine.

The initial inflammatory response may present as erythematous, eczematous, pruritic, or papulovesicular eruption in the area or boundary of the original design. Edema, anaphylaxis, and collapse are less common manifestations. The inflammation can result in scarring, keloid formation, and permanent, post-inflammatory pigment changes.

As demonstrated in my patient, hypopigmentation occurs more frequently in children than adults. Therapy includes protection of the blistered area, antihistamines, treatment of infection, and aggressive topical corticosteroid therapy.

This case was first presented at Maryland Derm, at the University of Maryland School of Medicine in Baltimore, by Dr. Martin, Dr. Vera David, and Dr. Anthony Gaspari.

_{Images courtesy Dr. Donna Bilu Martin}