Ingrown Toenail: How to Recognize and Treat It
Also known as: Onychocryptosis, Ingrowing Toenail, Ingrown Nail
What Is an Ingrown Toenail?
An ingrown toenail, known medically as onychocryptosis, occurs when the edge of the nail grows into the skin of the toe. This causes inflammation, pain, and sometimes a local infection. The condition is common: it affects an estimated 2.5% to 5% of the population, and incidence peaks in adolescents and young adults, with a male predominance of roughly 2 to 1. The big toe is by far the most commonly involved, particularly along the outer edge.
Causes and Risk Factors
Several factors contribute to ingrown toenails:
- Improper nail trimming, which appears to be the most common cause. Nails cut too short, or with the edges rounded rather than cut straight across, can curl and grow into the skin.
- Shoes that are too narrow, along with crowding of the toes.
- Excessive foot sweating (hyperhidrosis) and poor foot hygiene.
- Repeated trauma to the feet, including from sports and from ordinary daily activity.
- Heredity, which the American Podiatric Medical Association lists among the causes.
Intrinsic nail shape, such as a naturally curved or wide nail, is often blamed, but the evidence is debated: recent data suggest no difference in anatomical abnormalities between people with ingrown toenails and those without. Some medications, notably epidermal growth factor receptor inhibitors, may also play a role.
Symptoms
Typical signs include localized pain along the side of the nail, redness, swelling, and tenderness to touch or to pressure from shoes. If the toe becomes infected, drainage or pus can appear, sometimes with odor. Feeling tired and running a fever is a different signal: it suggests the infection has spread along the toe into the deeper layers of the skin (cellulitis), and it means you should see a doctor. Left untreated, overgrown tissue can build up around the nail.
Doctors generally recognize three stages: stage 1 with inflammation alone (pain, swelling, redness), stage 2 with acute infection and drainage, and stage 3 with hypertrophic granulation tissue.
Diagnosis
Diagnosis is clinical, made by direct observation of the toe by a primary care doctor, podiatrist, or dermatologist. It does not require laboratory or radiographic testing. An X-ray is occasionally used to rule out an underlying bony growth (subungual exostosis). If first-line treatment does not work, X-rays and cultures may also be used to rule out other conditions that can look similar, such as cellulitis, osteomyelitis, a foreign body, or a tumor.
Available Treatments
Treatment depends on the stage:
- Warm foot soaks several times a day for mild cases, followed by a topical antibiotic ointment.
- Cotton wisps or dental floss placed under the ingrown corner of the nail to redirect its growth, moistened with water or antiseptic. Gutter splints and taping are also used.
- Specialized podiatry care for persistent cases, where the ingrown portion is removed and topical or oral medication is prescribed.
- Surgery for recurring cases, performed under local anesthesia using a digital, metatarsal, or transthecal block. Options range from partial nail avulsion with chemical matrixectomy (typically using phenol) to total matrixectomy in severe cases.
Prevention
To reduce the risk:
- Trim nails straight across, without rounding the corners, and not too short.
- Wear properly fitted, roomy shoes, and avoid narrow footwear.
- Never tear or pick at the edges of a nail.
- Maintain good foot hygiene.
- See a podiatrist for nail deformities or repeated recurrence.
People with diabetes should be especially careful. Diabetes can cause nerve damage that makes it hard to feel an injury, and reduced blood flow that makes a sore or infection slow to heal, so a minor nail problem can turn serious. Daily foot checks should include looking for ingrown toenails.
When Should You See a Doctor?
See a doctor promptly for intense pain, pus or drainage, spreading redness, or fever. People with diabetes, peripheral vascular disease, or other circulatory disorders should avoid any form of self-treatment and seek podiatric care as soon as possible, given the risk of severe complications. The same caution applies to anyone with a weakened immune system or nerve damage.
Key takeaway: Ingrown toenails are common and usually mild, but an untreated infection can become more serious, especially in people with diabetes. Prompt care is recommended for any sign of inflammation.
Sources
- American Podiatric Medical Association (APMA), ingrown toenail causes, treatment, and prevention
- MedlinePlus, U.S. National Library of Medicine, ingrown toenail care, and when to see a doctor: severe pain, redness, swelling, or fever
- StatPearls, NCBI Bookshelf (NIH), ingrown toenails: epidemiology, staging, and management
- Surgical Strategies for Ingrown Toenails, PMC (NIH), when X-rays and cultures are used to rule out look-alike conditions
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), diabetes and foot problems