Fungal Nail Infection: Causes, Symptoms, and Treatment
Medically reviewed by Sumiran Racherla, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Fungal Nail Infection?
A primary care doctor, a dermatologist (a skin and nail doctor), or a podiatrist (a foot doctor) can diagnose and treat a fungal nail infection. These infections are not serious but can take a long time to treat. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is a fungal nail infection?
A fungal nail infection is a fungus growing in and around your fingernail or toenail. The medical name is onychomycosis.
These infections occur more often in toenails than in fingernails. They are most often seen in adults as they age.
Symptoms
You may have a fungal nail infection if your nail is brittle, discolored, or thicker than usual. Symptoms can include:
- Brittle nails or a change in nail shape.
- Crumbling of the outside edges of the nail.
- Debris trapped under the nail.
- A nail that loosens or lifts.
- White or yellow streaks on the side of the nail.
Fingernails and toenails can also change color or shape for many other reasons, including past injuries.
Causes and who gets it
Fungal nail infections often start after a fungal infection on the feet. Fungi can live on the dead tissue of the hair, nails, and outer skin layers.
You can get a fungal nail infection if your feet are constantly warm and damp.
You are at higher risk if you have:
- Diabetes.
- Poor blood flow in the legs, called peripheral vascular disease.
- Nerve damage in the feet or hands, called peripheral neuropathy.
- Moist skin for a long time.
- Immune system problems.
- A family history of nail infections.
- Footwear that does not let air reach your feet.
How doctors diagnose it
Your health care provider will examine your nails to find out if you have a fungal infection. Because other problems can change nails, talk to a provider about testing before you start treatment.
Looking at nail scrapings under a microscope can confirm the diagnosis and help find the type of fungus. A nail sample can also be sent to a lab for a culture, a test that grows the germ. Results may take 4 to 6 weeks.
Treatment
Treatment works best when it starts early. Medicine taken by mouth, which needs a prescription, is usually the best treatment. For toenails, you will need to take it for about 2 to 3 months. Fingernails need a shorter time.
These tablets can cause side effects such as headaches, an itchy rash, stomach ache, and feeling sick. Your provider will do lab tests to check for liver damage while you take them. You cannot take them if you have certain conditions, such as liver or kidney disease. Ask your provider whether they are safe if you are pregnant or breastfeeding.
A pharmacist may suggest an antifungal nail medicine that you brush onto the nail. You use it daily or weekly for 6 to 12 months. Over-the-counter creams and ointments usually do not help treat this condition.
Laser treatments may sometimes get rid of the fungus in the nails, but they are less effective than medicines. Badly infected nails sometimes need to be removed.
Nails grow slowly. Even if treatment works, it may take up to a year for a new clear nail to grow. Medicines clear up the fungus in about one half of the people who try them. Even when treatment works, the fungus may return. People with diabetes are at higher risk of the infection coming back.
When to see a doctor
Contact your provider if the fungal nail infection does not go away, or if your fingers become painful, red, or drain pus. See a provider if the infection has spread to other nails.
Get checked sooner if you have diabetes, because foot problems can be more serious. The same goes for a weakened immune system, such as after an organ transplant or during chemotherapy. Without treatment, a fungal nail infection can spread to the skin.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. A direct primary care doctor can look at your nails, arrange a nail sample for testing, prescribe treatment, and check the labs that go with it. They can also refer you to a dermatologist or podiatrist if the infection is severe or keeps coming back.
Common questions
Is a fungal nail infection serious?
Usually not. These infections are not serious but can take a long time to treat. People with diabetes or a weakened immune system should get checked sooner.
Can a fungal nail infection go away on its own?
It is best not to count on that. Left untreated, a fungal nail infection can spread to the skin. Treatment works best when it starts early, so talk to a healthcare provider about testing.
How long does it take to cure a fungal nail infection?
It takes a long time. The infection is cured when healthy nail grows back at the base. Even if treatment works, a new clear nail can take up to a year to grow.
How can I prevent a fungal nail infection?
A few habits can help prevent it. Keep your feet clean and dry, and wear clean socks every day. Wear flip-flops in gym or pool showers, and do not share towels or nail clippers. Treat athlete's foot as soon as possible so it does not spread to the nails.
Sources
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
