• Onychomycosis

    (Tinea Unguium; Fungal Nail Infection)


    Onychomycosis is an infection of the nail. The infection occurs more often on toenails than fingernails.
    Fungal Infection of the Toenails
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    Onychomycosis is caused by a fungus. 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. Factors that increase your chance of 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 artery disease (PAD)
    • Immune system disorders, such as HIV infection


    Onychomycosis can affect one or more nails. It most commonly occurs on toenails.
    Onychomycosis may cause:
    • 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:


    Antifungal medications are used to treat onychomycosis. Medications may be oral or topical.


    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 onychomycosis:
    • 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

    Foot Health Facts—American College of Foot and Ankle Surgeons http://www.foothealthfacts.org


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

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


    Garcia-Doval I, Cabo F, Montegagudo 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(5):877-887.

    Onychomycosis. EBSCO DynaMed Plus website. Available at: http://www.dynamed.com/topics/dmp~AN~T115521/Onychomycosis. Updated March 14, 2016. Accessed September 27, 2016.

    Rodgers P, Bassler M. Treating onychomycosis. Am Fam Physician. 2001;63(4):663-672.

    Thomas J, Jacobson GA, Narkowicz CK, et al. Toenail onychomycosis: an important global disease burden. J Clin Pharm Ther. 2010;35(5):497-519.

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