Is It Toenail Fungus Or Something Else? - Everyday Health

Health ConditionsFoot HealthToenail fungusShare this articleShareShare on FacebookShare on XShare on PinterestCopy LinkIs It Toenail Fungus or Something Else?

iStockByJennifer Acosta ScottUpdated on December 4, 2023Medically Reviewed bySusan Bard, MDON THIS PAGE

• Types of Infections
• Conditions That Look Similar
• Diagnosis and Treatment

ON THIS PAGE

• Types of Infections
• Conditions That Look Similar
• Diagnosis and Treatment

If you notice an odd spot on your toenail, you might assume it’s a fungal infection. However, there’s a good chance that it’s not.

Spots or discolorations on or under a toenail could be bruises resulting from trauma to the nail, blood blisters, warts, or even subungual melanoma, a type of skin cancer, says Ami Sheth, DPT, a podiatrist with Foot and Ankle Associates based in the San Francisco Bay area.

Since nail irregularities can be caused by diseases besides these as well, it’s best to get it looked at, says Dr. Sheth.

Richard Goad, DPT, with Baylor Scott & White Health in Waco, Texas, concurs. “Sometimes the nail will be the first place to show another underlying problem,” Dr. Goad says.

So is it a fungus, a false alarm, or another condition entirely?

Types of Toenail Fungal Infections

Toenail infections (onychomycosis) affect about 14 percent of the population at any given time, according to a study. The most common symptoms of a toenail fungal infection include discoloration of the nail, debris under the nail, irregularity of the white part of the nail, nail thickening, and pain, says Sheth.

Toenail fungal infections can usually be categorized into one of the following subtypes:

Distal Subungual Onychomycosis This is the most common form of toenail fungal infection, usually occurring in the portion of the nail closer to the tip and on the underside of the nail. The nail may become thick, yellow, or brittle.

Endonyx Onychomycosis People who have endonyx onychomycosis have fungus growing between the layers of the toenails. With this type of fungus, toenails usually have a milky white color and may be pitted or split. They usually don’t thicken or separate from the nail bed.

Proximal White Subungual Onychomycosis This is a relatively uncommon form of toenail fungus, seen most often in people with weakened immune systems due to conditions such as the human immunodeficiency virus (HIV). The fungus enters the toenail through the cuticle and affects the part of the nail closer to the base, turning it a whitish color.

White Superficial Onychomycosis This is also a rare form of toenail fungus that can occur in people who are otherwise healthy. It’s caused by a specific fungus that grows on the superficial, or top, layers of the toenail. Symptoms include opaque, white areas on the toenail that may eventually spread to cover the entire nail. The nail becomes soft and crumbly in texture.

Candida Infection of the Nail Candida is probably best known for causing vaginal yeast infections, but the fungus also lives on the skin. When there’s a break in the skin around the nail, called the nail folds, candida may enter and cause inflammation and infection. The nail itself may thicken and separate from the nail bed if the infection persists. “This type of fungal infection tends to affect fingernails more than toenails,” Goad says.

Conditions That May Look Like Toenail Fungus

Several health conditions can affect the appearance of your toenails and may be mistaken for toenail fungus.

Psoriasis Psoriasis can cause red, scaly patches on the skin. About half of people with skin psoriasis also have it on their nails, according to the National Psoriasis Foundation. Toenails and fingernails affected by psoriasis may be thick, discolored, crumbly, or loose.

In addition, research has found that people with nail psoriasis have a greater likelihood of having psoriatic arthritis, a type of arthritis that affects about 30 percent of people with psoriasis, according to CreakyJoints. In some cases, people with psoriatic arthritis may only see symptoms in their nails, rather than the skin.

Skin Cancer A discolored spot underneath a toenail may be a sign of melanoma, a potentially fatal form of skin cancer. Melanoma under a toenail usually looks like a brown or black streak or may appear similar to a bruise. Although this isn’t common, it’s also not rare, says Sheth. Her advice: “It’s always good to check it out.”

Lichen Planus This condition can affect other parts of the body, including the skin, nails, mouth, and genitals. Signs of lichen planus on the nails include nail ridges, thinning nails, splitting nails, and nails that separate from the nail bed, according to a report in Mayo Clinic Proceedings.

Yellow Nail Syndrome This rare condition has been known to cause slow-growing, thickened, yellow nails, along with abnormalities affecting the lungs and other parts of the respiratory tract and swelling in various parts of the body, according to the National Organization for Rare Disorders. The exact cause of the syndrome is unknown.

Alopecia Areata This autoimmune disorder most commonly causes round patches of hair loss from the scalp, although it can affect other areas of the body as well. Alopecia areata can also affect nails, which may become rough or pitted or develop white spots. Although rare, people with alopecia areata can notice nail changes before they start seeing hair loss.

Diagnosing and Treating Toenail Changes

If you notice changes in the appearance of your toenails, see a doctor promptly. If a fungal infection is suspected, a sample of the nail can be taken and analyzed by a lab to make a diagnosis. If the test comes back positive, an oral or topical antifungal medication may be prescribed to treat the fungus. Most antifungal medications are effective against most forms of toenail fungus, although treatment can take some time, in part because it’s hard to deliver any type of medication through the nail plate to the skin under the nail.

“Most of the time, the treatment requires the whole nail to grow out, which can take up to a year,” says Sheth. “Treatment needs to be consistent and long-term if it has any chance of working.”

If the test comes back negative for fungus, your doctor may begin investigating other causes for the abnormal appearance of your toenails. Sometimes symptoms involving other parts of the body help point to a diagnosis.

People with yellow nail syndrome, for example, may experience leg swelling or breathing problems. Those with alopecia could see their hair begin to fall out.

And, according to Goad, “With psoriasis, patches of red, scaly skin may be seen on the knees, elbows, and face, too. It’s usually not limited to just the toenails.”

Additional reporting by Susan Jara.

EDITORIAL SOURCESEveryday Health follows strict sourcing guidelines to ensure the accuracy of its content, outlined in our editorial policy. We use only trustworthy sources, including peer-reviewed studies, board-certified medical experts, patients with lived experience, and information from top institutions.SourcesAdditional Sources

• Ghannoum M et al. Fungal Nail Infections (Onychomycosis): A Never-Ending Story? PloS Pathogens. June 2014.
• Hands, Feet and Nails. National Psoriasis Foundation. December 22, 2022.
• Brody B. People With Nail Psoriasis May Have a Higher Chance of Developing Psoriatic Arthritis. CreakyJoints. April 14, 2021.
• Xie F et al. Nail Lichen Planus. Mayo Clinic Proceedings. May 2021.
• Yellow Nail Syndrome. National Organization for Rare Disorders. May 10, 2023.

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Susan Bard, MD

Medical Reviewer

Castle Connolly Top Doctor

Susan Bard, MD, is a clinical instructor in the department of dermatology at Weill Cornell Medicine and an adjunct clinical instructor in the department of dermatology at Mount Sinai in New York City. Her professional interests include Mohs micrographic surgery, cosmetic and laser procedures, and immunodermatology.

She is a procedural dermatologist with the American Board of Dermatology and a fellow of the American College of Mohs Surgery.

Dr. Bard has written numerous book chapters and articles for many prominent peer-reviewed journals, and authored the textbook The Laser Treatment of Vascular Lesions.

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Jennifer Acosta Scott

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Jennifer Acosta Scott is a writer for Healthday. Her career began in newspapers, and she has previously worked as a news reporter for the Tuscaloosa News, the Phenix Citizen, and the Weatherford Democrat. Acosta Scott's work has also been published in outlets like Health, Bankrate, Society Life, The Dallas Morning News, and the Fort Worth Star-Telegram.

She resides in the Dallas-Fort Worth area with her husband, Mark, and two sons, Patrick and Hayden. When she's not writing or spending time with her family, you can usually find Acosta Scott running in races, from 5Ks to marathons.

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