A sporadic case of congenital hypotrichosis simplex of the scalp: Difficulties in diagnosis and classification

Hereditary hypotrichosis simplex of the scalp is a genotrichosis characteri zed by a hair defect limited to the scalp in the absence of other ectoderma l or systemic abnormalities. Only large pedigrees consistent with autosomal dominant transmission have been described to date. In this article the cli nical and scanning electron microscopy findings of a nonfamilial case of co ngenital scalp hypotrichosis simplex are reported. In some patients the dia gnosis of sporadic hypotrichosis simplex of the scalp should be considered after ruling out all other possible causes of congenital and hereditary hyp otrichosis.