Flow cytometric assessment of clearance and relapse characteristics in psoriasis vulgaris after treatment with weekly clobetasol lotion under hydrocolloid occlusion versus twice-daily clobetasol ointment.

Clearance and relapse characteristics of clobetasol lotion under hydrocolloid occlusion once weekly versus clobetasol ointment twice daily were assessed in a comparative flow cytometric study. Quantitative analysis of markers for epidermal proliferation, differentiation and inflammation was performed on epidermal single cell suspensions prepared from 3-mm punch biopsies taken from 15 patients with psoriasis vulgaris before therapy, at clearance and 6 weeks after clearance. After treatment both therapy regimens resulted in substantial changes of all flow cytometric parameters, but clearance was induced earlier in the corticosteroid under hydrocolloid occlusion-treated group. With respect to the relapse phase no difference was observed between both treatments. Although it is remotely possible that the outcome in the treatment of more extensive psoriatic lesions might be different, the present study suggests that the robust clinical efficacy of the treatment with a topical corticosteroid under hydrocolloid occlusion is not associated with a rebound phenomenon.