Derm Dx: Rough, ridged fingernails and toenails

An 8-year-old male presents with his parents. They complain that for the past 4 months his nails have been “all messed up.“ He has no other medical problems.

The patient’s physical exam is completely normal with the exception of the appearance of his fingernails and toenails. All twenty nails have a roughened texture, as if they had been rubbed with coarse ...