Twenty-nail dystrophy in a girl with incontinentia pigmenti.

A 9-year-old girl with incontinentia pigmenti (IP) diagnosed soon after birth subsequently developed 20-nail dystrophy at the age of 3 years. This persists unchanged 6 years later, and she has no other evidence of any other cutaneous disease, nor a family history of IP or nail dystrophy. Twenty-nail dystrophy has been associated with a number of diseases including eczema, lichen planus, alopecia areata and psoriasis and a number of other congenital associations, but the association with IP appears to be unique.