Reliability of atopy patch tests in detecting protein sensitization in atopic dermatitis: a vehicle comparison

Atopy patch tests (APT) are used to detect sensitization to environmental proteins in triggering atopic dermatitis (AD). For APT, aeroallergens were usually used diluted in petrolatum. However, the production of this material has recently been stopped. A reliable alternative is needed. To determine the reliability of APT in liquid versus petrolatum to detect protein sensitization in AD. 47 adult patients with moderate-to-severe AD were tested with house dust mite (HDM) extracts. Two allergens were studied, Dermatophagoides farinae and Dermatophagoides pteronyssinus, using 3 vehicles: petrolatum and liquid vehicle with 2 concentrations (100 and 300 IR/mL). Patch tests were applied 2 days and evaluate at day 3. Petrolatum HDM-APTs detect a HDM-sensitization in 32 % of AD patients. Petrolatum HDM-APTs are more frequently positive than liquid APTs whatever the allergen. Although liquid HDM-APT results differed depending on the concentration, they exhibited better predictive values than petrolatum HDM-APTs, especially at 100 IR/mL. Liquid 100 IR HDM-APTs may represent a reliable alternative to petrolatum HDM-APTs to detect protein sensitization in AD.