Nail Disease for the Primary Care Provider.

Nail disorders are commonly seen by both primary practitioners and dermatologists. Nail disease spans a broad variety of diagnoses, including infectious, inflammatory, and neoplastic disorders. Dermatophyte onychomycosis can have clinical findings that overlap with other disorders, mandating adequate diagnosis before treatment is initiated. Periungual verrucae typically respond to keratolytics or cryotherapy, but may require topical immunotherapy or intralesional injections. Any verruca recalcitrant to treatment should undergo biopsy to rule out squamous cell carcinoma. Patients with longitudinal melanonychia or erythronychia involving a single digit should be evaluated by a dermatologist, with biopsy of nail matrix considered to rule out underlying malignancy.