Patch testing in atopic dermatitis

Because atopic dermatitis (AD) patients differ from non-AD patients in immunologic responses (they lack β-defensins, are more likely to react to protein allergens, and are harder to experimentally sensitize to the nonprotein allergens), patch-test responses to commercially available patch test series may differ in AD patients.

To compare responses to conventional patch tests in AD and non-AD patients and to assess the importance of specific allergens in AD.

AD patients were strictly defined by history of childhood flexural dermatitis. Patients with active disease were routinely pretreated with systemic antistaphylococcal and antiyeast antibiotics before patch testing unless contraindicated. All final patch-test readings occurred at day 7.

The overall number of positive patch-test results did not differ significantly in AD patients (n  =  146) versus non-AD patients (n  =  1,003). There was no significant increase in nickel sensitivity. There was a nonsignificant trend toward an increased number of positive patch-test reactions to tixocortol pivalate, Compositae mix, and propylene glycol in AD patients.

In AD patients treated with antibiotics and systemic azoles before patch testing, the number of positive patch-test reactions is almost identical to that of non-AD patients. Patch-test reactions to components of topical medicaments may be more frequent in AD as compared to non-AD patients.