Methods: A multi-center, retrospective chart review of PT within the last 5 years at allergy practices in three institutions. We report PT results using allergens in the Thin-Layer Rapid-Use Epicutaneous Test (TT) and additional supplemental allergens [North American Contact Dermatitis (NACD) Panel, Dormer® Cosmetic Panel, hairdresser’s panel, corticosteroid panel and personal products]. Additionally, patient characteristics including age, gender, occupation, dermatitis site, history of atopic disease and final diagnosis were also obtained.
Results: A total of 427 patients (mean age = 49.8 years) were patch tested. 82% were female. 54% reported an atopic history (history of asthma, atopic dermatitis, allergic rhinitis or food allergy). 30% were tested with TT, 60% with NACD panel, 30% with cosmetic series, 15% with corticosteroid series and 35% with personal products. The 5 most common positive PT allergens were nickel sulfate, fragrance mix I, P-phenylenediamine, thimerosal and cobalt chloride. The most common dermatitis sites were eyelid/periorbital (31%), facial (25%) and trunk (21%). 56.9% of patients were positive to at least one TT allergen. 25.6% of patients were positive to both a TT and a supplemental allergen (these patients would have been “partially evaluated” with TT allergens alone as they are positive to at least 1 TT allergen and 1 supplemental allergen). 12.5% of patients were negative to a TT allergen and positive to at least 1 supplemental allergen only (these patients would have been “missed” as they are negative to all TT allergens, but positive to at least 1 supplemental allergen).
Conclusions: Nickel remains the most common allergen. When evaluating patients with CD, testing with TT allergens alone would miss 12.5% of patients while 25.6% of patients would be only partially evaluated. As half of our patients were positive to at least 1 TT allergen, the TT remains an adequate screening tool but a more comprehensive panel may be needed to fully evaluate contact dermatitis.