2 Year Old with Nail Dystrophy

The patient is a two year-old girl with a 6 - 12 month history of a nail dystrophy.  Her brother had a similar process but this cleared without therapy after a few months.  Her pediatrician has prescribed ketoconazole cream which was not effective after 1 - 2 months.

O/E:  All nails on the left foot and two nail of the right foot are lusterless and show horizontal ridges and oil-droplet changes.  There is mild onycholysis.  Her fingernails are normal.  No other skin changes.

Clinical Photos:

The child was very apprehensive and for that  reason I did not do a KOH prep.

Diagnosis: In the differential diagnosis I included onychomycosis, evolving 20 Nail Distrophy and psoriasis.  I will see her back in 2 - 3 months. If there is no improvement, KOH prep will be performed.  I need to ask if either patent or sibling has a nail dystrophy.