Nail infections (Onychomycosis)

Onychomycosis refers to nail infections caused by any fungus, including yeasts and nondermatophyte molds. A study of 15,000 patients in Canada presenting to the offices of three dermatologists and one family physician found that 8 percent had onychomycosis.Toenail onychomycosis is most commonly due to dermatophytes . Fingernail onychomycosis is more likely than toenail onychomycosis to be due to yeast , and some studies have found that yeast are the most common cause of fingernail onychomycosis. Although onychomycosis is usually a cosmetic concern to patients, it also causes physical discomfort for some, particularly with more severe or advanced disease. Additionally, in patients with diabetes, onychomycosis may increase the risk of bacterial infections such as cellulitis.The great toe is usually the first to be affected, but all nails are susceptible. The disease begins with a whitish, yellowish, or brownish discoloration of a distal corner of the nail, which gradually spreads to involve the entire width of the nail plate and extends slowly toward the cuticle. Most studies have found that onychomycosis is responsible for only 50 to 60 percent of abnormal appearing nails. Treating onychomycosis is suggested to:
  • Patients with a history of cellulitis of the lower extremity who have ipsilateral toenail onychomycosis.
  • Patients with diabetes and toenail onychomycosis who have additional risk factors for cellulitis (ie, prior cellulitis, venous insufficiency, edema)
  • Patients who are experiencing discomfort/pain associated with infected nails.
  • Patients who desire treatment for cosmetic reasons.
Topical therapy

A topical antifungal nail lacquer containing ciclopirox is available for the treatment of mild to moderate onychomycosis.

Oral therapy

Newer medications such as terbinafine and itraconazole appear to have higher rates of cure in head-to-head randomized trials than older medications such as griseofulvin.


Surgical therapy involves removal of the nail. Surgery is generally only used to treat an isolated nail infection or in cases involving a dermatophytoma (a collection of dermatophytes in solid form under the nail).

Patients who desire treatment should be warned that treatment failures and recurrences are common, particularly for toenail onychomycosis.