Fingernail dystrophy in a young child

The patient is a 12-year-old Hispanic girl who presents with a 6-month history of nail dystrophy involving all of her fingernails. On examination, all 10 of her fingernails exhibit longitudinal ridging, pitting, fragility, thinning, and distal notching. The patient's mother is very concerned about the cosmesis of her daughter's nails. The patient has no systemic symptoms. On review of systems, ...