(Tinea Unguium; Fungal Nail Infection)
Onychomycosis is an infection of the nail caused by a fungus. The infection occurs more often on toenails than fingernails.
Fungal Infection of the Toenails
Onychomycosis is caused by a fungus that infects the nail. The fungi that cause onychomycosis survive in warm, moist environments. It is spread through direct contact with the fungus.
Anyone can get fungal nail infections. Risk factors that increase your chances of developing onychomycosis include:
Onychomycosis can affect one or more nails. It most commonly occurs on toenails.
- Thickened nail that is difficult to cut
- Brittle or ragged nail
- Discolored or unsightly nail
- Pain in the nail when doing ordinary activities
Your doctor will ask about your symptoms and medical history. A physical exam will be done. You may need to be referred to a doctor who specializes in skin and nail disorders (a dermatologist). The doctor may scrape or clip the nail to send a sample for testing. Results make take several weeks.
Tests on the nail sample may include:
- Examination under a microscope
Nails grow slowly. It can take up to a year to have a completely clear nail. Onychomycosis can be difficult to treat and may return after treatment. Talk with your doctor about the best treatment plan for you. Treatment options include the following:
- Prescription antifungal medicine taken by mouth—These medicines may work better than other treatments. Some people cannot take antifungal medicine. Talk your doctor about your health and any other medicines that you are taking.
- Topical antifungal treatments may be an option for certain people. This medicine may be less effective than taking an antifungal pill. It also has less risk of side effects, though.
To help reduce your chance of getting onychomycosis, take the following steps:
- Keep your feet clean. Dry them completely after washing.
- Keep your hands dry and wear rubber gloves when cleaning.
- Keep nails short and clean. Trim them straight across.
- Do not trim or pick at the skin near your nails.
- Avoid injuring your toenails.
- Avoid shoes that are too tight.
- Wear absorbent cotton socks. Change them if they become damp.
- Avoid walking barefoot around swimming pools, locker rooms, and other public places.
- Avoid artificial nails. They can trap moisture.
- If you have diabetes, see your doctor about steps you can take to control your blood sugar.
American Academy of Dermatology
American Board of Dermatology
College of Family Physicians of Canada
Garcia-Doval I, Cabo F, et al. Clinical diagnosis of toenail onychomycosis is possible in some patients: cross-sectional diagnostic study and development of a diagnostic rule. Br J Dermatol. 2010;163(4):743-751.
Nandedkar-Thomas MA, Scher RK. An update on disorders of the nails. J Am Acad Dermatol. 2005;52:877-887.
Onychomycosis. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/about/about-us. Updated July 27, 2012. Accessed December 3, 2012.
Rodgers P, Bassler M. Treating onychomycosis. Am Fam Physician. 2001;63:663-672,677-678.
Thomas J, Jacobson GA, et al. Review article. Toenail onychomycosis: an important global disease burden. J Clin Pharm Ther. 2010;35(5):497-519.
Last reviewed December 2013 by David L Horn, MD, FACP
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.