Renbök phenomenon in alopecia areata.

We present a second case of alopecia areata sparing a congenital nevus of the eyebrow. This inverse counterpart of perinevoid alopecia is discussed and placed in context to the recently described Renbök phenomenon. According to the present definition of a nevus as a genetic mosaic, a genetically determined resistance to alopecia areata is suggested in our case. Copyright 2000 S. Karger AG, Basel.