Contact sensitization to cosmetic series of allergens in patients with rosacea: A prospective controlled study

BACKGROUND: Previous studies have documented the cosmetic allergic contact dermatitis due to common cosmetic allergens in standard series and various cosmetic products used in rosacea patients; however, the prevalence of contact sensitization to other cosmetic allergens other than those in standard series is largely unknown. AIMS: To assess the prevalence of contact sensitization to a European cosmetic series of allergens (Chemotechnique Diagnostics AB, Malmo, Sweden) in rosacea patients and to compare this with the prevalence observed in general population. METHODS: In this prospective monocenter study, 103 patients with rosacea and 104 control subjects were investigated for contact sensitizations via patch testing the cosmetic series including 49 allergens. RESULTS: At least one positive allergic reaction was observed in 62 (60.2%) rosacea patients, and in 25 (24.0%) control subjects. Compared with control subjects, rosacea patients were statistically more likely to have positive patch tests. The most common allergens giving positive results were octyl gallate (10.68%), dodecyl gallate (8.74%), tert-Butylhydroquinone (7.77%), thimerosal (6.80%), euxyl K400 (6.80%), cocamidopropyl betaine (5.83%), and 2,6-Di-tert-butyl-4-cresol (4.85%). CONCLUSIONS: This study shows that rosacea patients show a strikingly high prevalence of contact sensitization to cosmetic allergens. We recommend the additional use of cosmetic series for patch testing, and the careful use of cosmetics in rosacea patients if cosmetic contact sensitivity is suspected.