Topical medicaments are a common cause of allergic contact dermatitis. This study will evaluate the prevalence of contact allergy to a wide array of topical medicaments at the Ottawa Patch Test Clinic.
The objectives of this study are to report the results of positive patch testing to topical medicaments at the Ottawa Patch Test Clinic and identify common sensitizers in topical medicaments.
Patients were tested with the standard North American Contact Dermatitis screening series of 70 allergens plus supplementary allergens when indicated. A retrospective chart review of patients positive to topical medicaments between January 1, 2000, and September 30, 2010, was undertaken.
The average age of patients was 49.5 years. Thirty-four percent were atopic. Common sensitizers included topical antibiotics (58%), steroids (30%), anesthetics (6%), and antifungals (6%). Patch testing showed that 61% of patients tested positive to antibiotics, 21% to topical steroids, 17% tested positive to topical anesthetics, and 1% tested positive to topical antifungals. The most common reactions were to bacitracin (44%) and neomycin (29%). The most common steroid screener was tixocortol-17-pivalate (group A) (19%), and the most common local anesthetic was lidocaine (12%).
Topical medicaments of all kinds are common causes of allergic contact dermatitis. Those that are more readily available, in over-the-counter preparations, are the most frequent culprits.