Dystrophia unguium mediana canaliformis.

Abstract

Dystrophia unguium mediana canaliformis is a very rare and rather bizarre change affecting one or more nails, usually the thumb nails, in which a central, longitudinal, dark-colored streak appears for no apparent reason. Robinson and Weidman1reported a case in 1948 and listed the few previously reported cases back to the original one described in 1928 by Heller,2who named the condition. The following case seems worth recording because of its curious periodicity and the exact symmetry of the lesions in the two thumbs. REPORT OF A CASE The patient was a fit, slightly built man of 33. He presented himself complaining of an abnormality of both thumb nails, illustrated in figure 1. About seven weeks before I saw him he had noticed a defect at the base of each thumb nail. There was no discomfort and no apparent inflammation of the perionychial tissues. As the nails grew