Treatment with topical tacrolimus favors chronic actinic dermatitis: A clinical and immunopathological study

Background: Previous studies have demonstrated the efficacy and safety of tacrolimus ointment in the treatment of atopic dermatitis (AD); however, few have investigated the effect of tacrolimus on chronic actinic dermatitis (CAD).Objectives: To investigate the efficacy and safety of tacrolimus ointment on CAD and its mechanism of treatment.Methods: Forty adult patients with CAD were treated with 0.1% tacrolimus ointment. Skin biopsies were performed on 15 patients before and after treatment. The specimens were subjected to immunohistochemical staining with a panel of monoclonal antibodies to CD1a, CD11b, and CC chemokine receptor 7.Results: Among all the 40 patients, two (5%) were clinically cured and 23 (57.5%) achieved excellent results, making a total effective rate of 62.5%; 14 (35%) were improved; and one (2.5%) case was withdrawn due to intolerable itching at the locally applied areas. CD1a, CD11b and CCR7 expression were all significantly down-regulated after topical treatment with tacrolimus.Conclusions: Treatment with topical tacrolimus is effective and safe for chronic actinic dermatitis, probably due to suppression of the function of Langerhans' cells and inflammatory dendritic epidermal cells and their relevant cytokines.