Poster

Introduction: Contact sensitization to topical drugs, a frequent cause of allergic contact dermatitis, may hinder their topical or even systemic use. The EDEN fragrance study assessed the prevalence of contact sensitization to topical drugs in the general population of five European countries.<br/><br/>Objectives: To report the crude prevalence of contact allergy to topical drugs and identify the clinical relevance.<br/><br/>Methods: Within a sample of individuals from the general population who were patch tested with T.R.U.E. Test®, we evaluated the crude prevalence of contact sensitization to wool alchools (1000 mcg/cm2), neomycin (600 mcg/cm2), caine mix 630 mcg/cm2 (benzocaine, tetracaine and dibucaine), quinoline mix 190 mcg/cm2 and three different topical corticosteroids (budesonide 1 mcg/cm2, tixocortol pivalate 3 mcg/cm2 and hydrocortisone butyrate 20 mcg/cm2). Combining patch test results with reported avoidance of topical drugs in their lifetime or a previous diagnosis of contact dermatitis, we assessed the possible clinical relevance of positive reactions.<br/><br/>Results: Among 3119 patch tested individuals (54.9% females, mean age 44.2 ± 16.0 years), the crude prevalence of contact sensitization for topical drugs was 2.1%, with 0.8% occurring within the group of topical steroids and 0.4% with neomycin, caine mix or wool alchools. Reactivity to topical drugs was not associated with avoidance of topical drugs, but significantly associated with a previous diagnosis of contact dermatitis (3.7%), especially for wool alchools (1.1%), neomycin (1.3%) and tixocortol pivalate (0.9%). When controlling for sex, a previous diagnosis of atopic dermatitis or psoriasis there was no significant difference.<br/><br/>Conclusions: Our results indicate that, although relatively low, sensitization to topical drugs may be significant, especially in individuals who have had contact dermatitis, whom we may assume have relevant reactions. Sensitization to neomycin, an antibiotic that may crossreact with other aminoglicosides for systemic use may not be irrelevant, suggesting the need to further restrict its topical use.