Topical Steroid Induce Demodicidosis as a Presentation of Hemifacial Rosacea-Like Lesion

Demodex mites share a commensal relationship with humans, and they asymptomatically parasitize the pilosebaceous follicles of humans. In healthy skin, the density of the mites is normally low, and this low density does not cause skin diseases. When the density of these mites increases, they induce facial skin diseases. We describe a 27-year-old male who presented in our outpatient department with a 10-year history of red and itchy skin lesions on the right side of his face. Determination of the density of Demodex folliculorum on the right cheek by standardized skin surface biopsy (SSSB) revealed a density of 20 Demodex/cm. On the contrary, the left face revealed a density of 2 Demodex/cm. The density of D. folliculorum declined after treatment with oral metronidazole. The redness of the right cheek improved. Herein, we will introduce the method of modifi ed SSSB, which will be more suitable and useful for Taiwan dermatologists in their daily practice. (Dermatol Sinica 27: 111-116, 2009)