Influence of vitamin C on the elicitation of allergic contact dermatitis to p-phenylenediamine.

ABSTRACT

BACKGROUND: Hair dyes represent one of the most important causes of allergic contact dermatitis resulting from the use of cosmetic products. The principal causative chemistry is associated with oxidation products of p-phenylenediamine (PPD) and closely related substances. OBJECTIVES: To examine whether prior application of the antioxidant vitamin C to the skin was able to reduce the cutaneous allergic response to PPD. METHODS: Twenty eight volunteers with a proven history of contact allergy to PPD were recruited. Each was tested with a range of PPD doses and PPD-containing hair dye on untreated skin and skin pretreated for 10 min with a vitamin C formulation. RESULTS: Pretreatment of skin sites with vitamin C led to a reduction in the intensity, or even ablation, of the cutaneous allergic reaction to PPD in ∼75% of cases as compared with untreated skin. CONCLUSIONS: The results suggest that treatment of the skin adjacent to the hair-bearing area with antioxidant could form part of a strategy to reduce the burden of cosmetic allergic contact dermatitis caused by hair dyeing.