Ask an Expert: How do I get rid of a wart under my nail?

What is a wart, and how do I know if I have one?

Both common warts and warts around the nail (periungual warts) are typically caused by the same human papilloma virus (HPV), explains Adam Friedman, MD, FAAD, Associate Professor of Dermatology and Residency Program Director at the George Washington School of Medicine and Health Sciences. “When they first start, they are pinhead in size, shiny, smooth, translucent and usually discrete. They grow in weeks or months to pea size, become rough, dirty brown, grey or black and horny. These warts can even become fissured, inflamed and tender.”

The “warty” surface appearance is caused by small projections from the skin. Warts can grow together into a bigger wart with a scalloped edge when infected skin cells spread the virus to cells nearby, according to Bob Brodell, MD, FAAD, Professor and Chair of the Department of Dermatology at the University of Mississippi Medical Center. “Blood vessels extend very close to the surface of warts. They bleed easily when bumped and often show crusting on the surface,” Dr. Brodell explains. “When the superficial blood vessels in a wart clot, they produce black dots sometimes called the ‘seeds’ of a wart.” 

How do warts get under the nail?

“The warts start in the skin surrounding the nail and are called periungual warts. Then they can extend underneath the nail, becoming subungual warts,” says Steve Daveluy, MD, FAAD, Assistant Professor of Dermatology at Wayne State University. “You can usually recognize warts around the nail because they cause thickening of the skin, usually with a rough, dry surface. Once they begin to grow under the nail, they will often disrupt the growth of the nail and cause a portion of it to stop growing.”

The nail growth is disrupted by damage to the nail matrix, where the nail is made, according to Dr. Friedman, and nail bed warts can also cause the nail plate to separate from the skin beneath it.

Watch out for warts that don’t come under the nail from the outside. “If a patient has something that is completely underneath the nail without extending from the outside, it is probably not a wart,” Dr. Daveluy explains. “They should have that lesion examined by a dermatologist.” 

CAUTION! Sometimes a wart isn’t just a wart. 

Get your stubborn warts checked out by a dermatologist! The virus that causes warts can also cause cancer. “For warts that don’t resolve or don’t respond to treatment, it’s important to see a dermatologist since the HPV virus that causes warts can increase the risk of squamous cell cancer,” says Dr. Daveluy.

Dr. Friedman also stresses the importance of seeing a dermatologist. “A form of nonmelanoma skin cancer called a squamous cell carcinoma can mimic a subungual wart. Certain forms of the HPV virus can ultimately cause the infected skin to turn into this type of skin cancer, so consulting with a dermatologist is key.”

If your dermatologist isn’t sure about your wart, they’ll play it safe and test it, as Dr. Brodell explains: “Sometimes it is impossible to tell if a lesion is a wart and, in that case, we will sometimes perform a biopsy on a lesion, especially lesions that might be warts evolving into squamous cell skin cancer.”

How can I get rid of a subungual wart?

Sometimes, warts go away on their own. If they don’t, it’s still a good idea to get a wart looked at by a doctor in the early stages. “Most warts will eventually resolve spontaneously, once the immune system recognizes and attacks the virus,” Dr. Daveluy says, but also cautions that warts that don’t go away or respond to treatment need to be evaluated by a dermatologist.

If you want to get a periungual or subungual wart removed (for medical peace of mind or aesthetic reasons, both are completely valid), your dermatologist has a wide arsenal of tools to help treat the problem. As Dr. Brodell puts it, “If we had a perfect wart treatment for everyone, we would not have so many options!  Sometimes we try several different treatments before we find the one that works best for each individual.”

Warts under the nail are often more resistant to treatment than common warts and they recur frequently, Dr. Friedman explains, which is why the most effective approach uses treatments that both kill the infected skin cells and stimulate the immune system to take care of the wart virus in the surrounding skin.

If the nail is protecting the wart, it may need to be trimmed back before treatments can be applied. Therapies that destroy infected skin cells include cryotherapy (freezing), chemical cauterization with substances like salicylic acid or “beetle juice” (a blistering agent called cantharadine derived from the blister beetle), or lasers that block off the blood vessels supplying the wart.

Persistence is important, and you need to be prepared to tough out multiple treatments.  “Periungual warts, as well as plantar warts, often require multiple treatment sessions, usually spaced several weeks apart. It is certainly a work in progress and can be the source of long standing patient frustration and discomfort,” Dr. Friedman says. Dr. Daveluy cautions that wart “treatments can be painful, especially around the fingertips and around the nails.” Treatment is worth the discomfort when the wart is gone, and with it the risk of nail disruption or worse.

ATTENTION NAIL BITERS:

Nail biting is considered a risk factor for subungual warts, and is a good way to spread them to other fingers – or your lips! Kick your nail biting habit to help keep warts at bay.

How can I prevent warts under the nail?

Dr. Brodell recommends “common sense” hygiene – wash your hands several times daily and avoid direct contact with other people who have warts. Warts are contagious! “When the skin is damaged, it also increases the risk of catching the wart virus,” Dr. Daveluy says. “This includes dry, cracked skin, so it’s important to take care of your skin and use moisturizer.”

Most importantly, according to Dr. Brodell, “if you get a wart, it should be treated promptly.  Smaller warts are easier to remove by any treatment modality than large warts.  Also, we want to get rid of one wart before it spreads and then there may be 10 to treat!”

Thank you so much to Dr. Brodell, Dr. Daveluy, and Dr. Friedman of the American Academy of Dermatology  for lending us their expertise! The American Academy of Dermatology offers great free resources on taking care of your skin, hair, and nails, which you can find here.