Rosacea: a study of clinical patterns, blood flow, and the role of Demodex folliculorum.

BACKGROUND: Rosacea is a common facial eruption that has various clinical presentations.

OBJECTIVE: We studied blood flow in lesional skin and explored the role of Demodex folliculorum in patients with rosacea.

METHODS: A survey of clinical presentations was made in 108 patients with rosacea. Facial blood flow was studied by laser-Doppler flowmetry. The presence of Demodex was determined by microscopy of skin samples.

RESULTS: The sex incidence was equal. The incidence peaked in the fourth and seventh decades of life. Lymphedema was common and was seen in 26 patients. Rhinophyma was present in 15 patients, mostly men. Eleven patients were black, an unexpectedly high number. Laser-Doppler flowmetry showed that lesional blood flow was three to four times that of control subjects. Demodex folliculorum was found in 20 of 25 rosacea patients examined but in only 2 of 20 control subjects.

CONCLUSION: The findings indicate that the papillary dermal vasculature is dilated in rosacea. Demodex may be present. These findings give no definitive clue as to the origin of the disease.