Contact Allergy in Patients with Rosacea. / Sensibilización alérgica de contacto en pacientes con rosácea.

ABSTRACT

BACKGROUND AND OBJECTIVE: Rosacea is a chronic acneiform skin disorder in which impaired skin barrier function can lead to sensitization to allergens. We aimed to analyze contact allergies in our patients with rosacea. MATERIAL AND METHODS: Retrospective cohort study of all patients who underwent patch testing in our skin allergy clinic between May 1991 and May 2019. RESULTS: A total of 200 patients with rosacea were referred to our clinic for patch testing during the study period; they represented 2.1% of all patch tested patients in the period. Eighty-one percent were women (mean age, 44.7years). At least 1positive patch test was recorded for 46.5%; 15% were of current relevance. The most frequent positive reaction was to nickel (26%), followed by cobalt chloride (6.5%), isothiazolinones (6%), p-phenylenediamine (5.5%), fragrance mixII (5%), and thimerosal (3.5%). The most common currently relevant patch test reactions were to isothiazolinones in 10 of the 200 patients (5%); to phenylenediamine, fragrance mixII, and toluensulfonamide formaldehyde resin in 4 patients (2%) each; and to tixocortol and fragrance mixI in 2 patients (1%) each. The allergen groups most often implicated were metals (of current relevance in 12.6%) and drugs (of current relevance in 25.8%). Preservatives and fragrances were the next most common allergen groups, and 70.8% and 43.7% of the positive reactions in these groups, respectively, were of current relevance. Cosmetics were the most frequent source of sensitization, followed by topical medications - notably corticosteroids and antifungal agents. CONCLUSIONS: We emphasize the high prevalence of allergic contact dermatitis in patients with rosacea, a finding which supports patch testing, especially if eruptions worsen when these patients use cosmetics and topical medications.