• Onychomycosis

    (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
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    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.

    Risk Factors

    Anyone can get fungal nail infections. Risk factors that increase your chances of developing onychomycosis include:
    • Wearing shoes that trap in moisture and warmth, such as workboots
    • Increased age
    • Having athlete's foot
    • Having an injury to the nail
    • Type 1 or Type 2 diabetes
    • Circulatory disorders, such as peripheral vascular disease
    • Immune system disorders, such as HIV


    Onychomycosis can affect one or more nails. It most commonly occurs on toenails.
    Symptoms include:
    • 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:
    • Culture
    • 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 a antifungal pill. It also has less risk of side effects, though.


    Surgery to remove the nail is sometimes done in severe cases. A new nail grows in its place unless the nail matrix that makes the nail is destroyed.


    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 http://www.aad.org/

    American Board of Dermatology http://www.abderm.org/


    College of Family Physicians of Canada http://www.cfpc.ca/

    Health Canada http://www.hc-sc.gc.ca


    Garcia-Doval I, Cabo F, Monteagudo B, 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: http://www.ebscohost.com/dynamed/what.php . 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, Narkowicz CK, et al. Review article. Toenail onychomycosis: an important global disease burden. J Clin Pharm Ther . 2010;35(5):497-519.

    Revision Information

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