Unilateral demodectic rosacea.

A unilateral rosacea-like chronic dermatitis of the right side of the face was shown to harbor innumerable Demodex folliculorum and D. brevis. Treatment with oral metronidazole suppressed the dermatitis but did not significantly reduce the Demodex population. Treatment with topical crotamiton eliminated the Demodex and was curative. These observations support the view that D. folliculorum and D. brevis may be pathogenic when they are present in extremely large numbers.