Twenty-three patients, 18 males and five females, all suffering from rosacea, were investigated. Patients applied 3% sulfur to one side of the face and a placebo of vehicle to the other side for a period of 28 days. After the 28-day period a clinical assessment and 3 mm punch biopsy for mite counts were carried out. The whole trial was conducted using a double-blind method. The trial provided no significant evidence to indicate that the prevalence of Demodex folliculorum is related either to the treatment of rosacea with 3% sulfur or to the clinical assessment, although there was evidence that the treatment did have a real effect as judged clinically.
ROBINSON TWE. Demodex Folliculorum and RosaceaA Clinical and Histological Study. Arch Dermatol. 1965;92(5):542–544. doi:10.1001/archderm.1965.01600170058008