Psoriasis of the Nail

A 43-year-old man sought treatment of a “fungal nail infection” that had been present for several years. The condition had not responded to standard dosages of itraconazole, terbinafine, and fluconazole prescribed by another physician.

When Ted Rosen, MD, of Houston examined the patient, he noted wavy nail dystrophy, keratotic subungual debris, and marked pitting of the nail surface; all 10 fingernails were involved. The toenails were normal, as was the remainder of the skin examination. A presumptive diagnosis of psoriasis of the nail was made.

About half of cases of nail dystrophy result from fungal infection. Other causes include inflammatory disease (psoriasis and lichen planus), viral infection (subungual wart), neoplasia (subungual squamous cell carcinoma, keratoacanthoma, and osteoma), multisystem diseases (Reiter syndrome, sarcoidosis, and renal or hepatic insufficiency), and metabolic disorders (thyroid abnormalities and iron deficiency).

This patient refused injection of a dilute corticosteroid into the posterior nail fold, and application of clobetasol gel to the same area failed to resolve the nail dystrophy. Six months later, the development of widespread typical truncal psoriasis confirmed the previous diagnosis. The patient is currently being treated with efalizumab, a new biologic agent.