P-Phenylenediamine and Risk of Sensitization in Children

Abstract

Contact allergy to p-phenylenediamine (PPD) in children has been described over almost 2 decades, indicating a major problem. PPD can be found in permanent hair dyes and temporary henna tattoos. Children often get sensitized to PPD at a relatively young age when getting a temporary henna tattoo while away on holiday in exotic surroundings. This results in a localized acute allergic reaction at the site of the tattoo within 1–2 weeks after the tattoo has been drawn. The symptoms will clear over weeks on treatment with topical corticosteroids. However, sensitization to PPD will be life-long and may later result in very severe allergic reactions if re-exposure to PPD happens, e.g., by hair dyeing. Population-based studies indicate that even young children may get their hair dyed and that many teenage girls dye their hair regularly. Exposure to permanent hair dyes with PPD and related substances may in itself lead to PPD sensitization and severe allergic reactions. The allergic reaction will typically develop within hours after dyeing the hair, with clinical presented symptoms such as facial edema and facial dermatitis, which also may generalize. This may lead to hospital admission and treatment with systemic corticosteroids. It is important to note that this is a delayed-type hypersensitivity reaction and should be treated as such. Antihistamines have no effect in this situation. PPD sensitization may have long-term carrier consequences, as, for example, PPD contact allergy in a teenage girl may hinder her entering the hairdressing trade. Patch testing is used to make the diagnosis of PPD sensitization. In children with severe clinical reactions to temporary henna tattoos and/or permanent hair dyes, it is advisable to start the patch testing with PPD in a low concentration, e.g., 0.01 % PPD in petrolatum. It is not recommended to get temporary henna tattoos under any circumstances and children under the age of 16 years should not use permanent hair dyes in order to avoid severe allergic reactions and life-long sensitization to PPD.