Rosacea-Like Demodicosis Induced by Topical Pimecrolimus: Immunohistochemical Evaluation of Inflammatory Infiltrate

A B S T R A C T We present a 48-year-old female patient who developed rosacea-like demodicosis after seven days of topical application of 1% pimecrolimus cream. The inflammatory infiltrate in the lesions was mainly composed of T-cells with a CD4+/CD8+ ratio = 0.33; B-cells (CD20+) and NK-cells (CD56+) were not detected. Large numbers of (CD68+) histiocytes were demonstrated, whereas the number of Langerhans cells (CD1a+) revealed no significant alteration. The reduced CD4+:CD8+ ratio may have led to a modification of follicular microenvironment favouring the excessive proliferation of Demodex mites, who triggered a presently unknown sequence of events leading to the development of pimecrolimus-induced rosacea-like demodicosis.