Allergens in Common Brands of Clobetasol

Topical corticosteroids are one of the most commonly prescribed medications by dermatologists.¹ Allergic contact dermatitis (ACD) to topical corticosteroids has been widely recognized since the late 1980s.² Allergy to corticosteroids often presents as irritation, worsening of dermatitis, or ineffectiveness of treatment with topical corticosteroids.² When patch testing for suspected allergy to corticosteroids, a corticosteroid series should be used which consists of select corticosteroid chemicals in a vehicle like alcohol or petrolatum.³ Interpreting the results of corticosteroid patch testing is difficult because the anti-inflammatory effect of topical corticosteroids can cause false-negative results at early readings.^3,4 Thus reactions such as macular erythema and edge effects often necessitate a second reading, at days 7 to 10, once the initial anti-inflammatory effect has decreased.^4-6 A positive patch test for commercial corticosteroids can be misleading as it may indicate an allergy to preservatives or vehicles used in its preparation.^2,7 A majority of topical corticosteroids contain at least one potential allergen in their vehicle.⁷

Previous studies have compared the prevalence of allergenic ingredients in the corticosteroid class between generic and branded products generally.⁷ More generic products were free of allergens than branded products.⁷ What is not well characterized is whether the presence of allergenic ingredients differs among specific brands. This study aimed to assess the frequency of allergenic ingredients in various brands of clobetasol propionate.