Nail Fungus: FAQs
What is nail fungus?
Nail fungus, also called onychomycosis, is a fungal infection that can affect both your toenails and fingernails. Nail fungus almost never goes away on its own, and it can spread. Your dermatologist knows how to treat nail fungus, even stubborn cases.
Nail fungus often develops on the big or second toe.
Nail fungus often develops on the big or second toe. This patient’s big toe has common signs of nail fungus, such as discoloration, lifting, and redness on the surrounding skin.
Is nail fungus contagious?
Yes. It spreads from one person to another. You can develop nail fungus if you:
Touch fungi on someone’s skin or nail.
Share items with fungi on them, such as an unwashed towel or nail clippers.
Walk barefoot in a warm, moist place like a pool deck, public shower, or locker room.
Can you get nail fungus from having dirty nails?
Dirty nails alone cannot cause nail fungus. Keep in mind that certain types of fungi cause nail fungus. For someone to develop nail fungus, the fungi that cause it must get into a nail or a microscopic opening in the skin around a nail. When this happens, you can develop nail fungus.
Keeping your nails clean, short, and dry can help prevent nail fungus.
Can you spread nail fungus to other parts of your body?
Yes. If one of your nails is infected with nail fungus, you can spread it to other nails. This can happen when the infected nail touches a healthy nail or the skin around another nail.
Using everyday items can also spread nail fungus. For example, if you use nail clippers to trim the infected nail and then trim nails that haven’t been infected, you can spread nail fungus to the other nails.
You can also develop nail fungus if you have athlete’s foot. Athlete’s foot is a fungal infection on the skin. If the fungal infection on your foot spreads to a nail, you can develop nail fungus. It’s common for people to develop nail fungus this way. Board-certified dermatologist Boni Elewski, MD, FAAD, says, “You may not even know you have athlete’s foot.” If the athlete’s foot is mild, you may think you have dry feet.
How do you know if you have nail fungus?
The first sign is usually a change to the infected nail. You may notice a different color on part of a nail. Other signs of nail fungus that you may notice include a brittle nail that cracks or splits and buildup under a discolored nail.
If you spot any of these signs, it’s helpful to see a board-certified dermatologist. This doctor specializes in treating not only the skin, but nails, too. Dermatologists have expertise in diagnosing and treating nail conditions. Sometimes, testing is needed to diagnose nail fungus and treat it effectively.
Can you scrape away nail fungus?
No. While it may seem that scraping away the buildup beneath (or on) a nail will get rid of the infection, you’ll only remove some of the fungi. The fungi also live in the nail and the tissue beneath the nail.
Can you file nail fungus from your nails?
No. The fungi live in the nail and tissue beneath the nail. As such, filing cannot get rid of all the nail fungus.
Can toenail fungus be cured?
Yes. Fungus on toenails and fingernails is treatable, especially when the infection is caught early and is mild. To clear a fungal nail infection, prescription medication is necessary. Some patients apply this medication to the infected nails. Other patients take a pill.
Keep in mind that it takes time to see improvement. For example, if you have nail fungus on your big toe and your dermatologist prescribes medication that you take for 3 months, this treatment can get rid of the fungal infection. However, you’ll still see the nail changes caused by the infection like discoloration and lifting.
To see a clear nail, the nail must grow out. Since nails grow slowly, this can take months. On the big toe, it may take a year or longer to see a clear nail.
Is nail fungus serious?
Most people with nail fungus go about their everyday lives without a problem. Some say they feel embarrassed or anxious because of the changes to the infected nail(s).
Left untreated, however, nail fungus sometimes becomes serious. It can cause pain or misshapen nails. If either happens to a toenail, it can interfere with your ability to walk or stand. If you’re experiencing pain or discomfort or having difficulty walking or standing, proper treatment is important.
To see what nail changes can occur, go to Nail fungus: Signs and symptoms.
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References
Elewski BE, Aly R, “Efficacy and safety of tavaborole topical solution, 5%, a novel boron-based antifungal agent, for the treatment of toenail onychomycosis: Results from 2 randomized phase-III studies.” J Am Acad Dermatol. 2015 Jul;73(1):62-9.
Evans A. “What's the fuss about fungus?” Dermatol World. 2024 Jan;34(1):22-9.
Falotico JM, Lipner SR. “Updated perspectives on the diagnosis and management of onychomycosis.” Clin Cosmet Investig Dermatol. 2022 Sep 15;15:1933-57.
Kreijkamp-Kaspers S, Hawke K, et al. “Oral antifungal medication for toenail onychomycosis.” Cochrane Database Syst Rev. 2017 Jul 14;7(7):CD010031.
Scher RK, Tavakkol A, et al. “Onychomycosis: Diagnosis and definition of cure.” J Am Acad Dermatol. 2007 Jun;56(6):939-44.
Stewart CR, Algu L, et al. “Effect of onychomycosis and treatment on patient-reported quality-of-life outcomes: A systematic review.” J Am Acad Dermatol. 2021 Nov;85(5):1227-39.
Written by:
Paula Ludmann, MS
Reviewed by:
William Warren Kwan, MD, FAAD
Shari Lipner, MD, PhD, FAAD
Temitayo Ogunleye, MD, FAAD
Last updated: 6/26/25