DefinitionAn ingrown toenail occurs when the edge of the nail grows down and into the skin of the toe. There may be pain, redness, and swelling around the nail.
Alternative NamesOnychocryptosis; Unguis incarnatus; Nail avlusion; Matrix excision
Causes, incidence, and risk factorsAn ingrown toenail can result from a number of things, but poorly fitting shoes and toenails that are not trimmed properly are the most common causes. The skin along the edge of a toenail may become red and infected. The great toe is usually affected, but any toenail can become ingrown.Ingrown toenails may occur when extra pressure is placed on your toe. Most commonly, this pressure is caused by shoes that are too tight or too loose. If you walk often or participate in athletics, a shoe that is even a little tight can cause this problem. Some deformities of the foot or toes can also place extra pressure on the toe.Nails that are not trimmed properly can also cause ingrown toenails.When your toenails are trimmed too short or the edges are rounded rather than cut straight across, the nail may curl downward and grow into the skin.Poor eyesight and physical inability to reach the toe easily, as well as having thick nails, can make improper trimming of the nails more likely.Picking or tearing at the corners of the nails can also cause an ingrown toenail.Some people are born with nails that are curved and tend to grow downward. Others have toenails that are too large for their toes. Stubbing your toe or other injuries can also lead to an ingrown toenail.
Signs and testsAn examination of the foot will show the following:Skin along the edge of the nail will appear to be growing over the nail, or the nail may seem to be growing underneath the skin.Skin may be swollen, firm, red, or tender to touch. At times, there may be a small amount of pus present.Tests or x-rays are usually not needed.
TreatmentIf you have diabetes, nerve damage in the leg or foot, poor blood circulation to your foot, or an infection around the nail, go to the doctor right away. Do NOT try to treat this problem at home.To treat an ingrown nail at home:Soak the foot in warm water 3 to 4 times a day if possible. Keep the toe dry, otherwise.Gently massage over the inflamed skin.Place a small piece of cotton or dental floss under the nail. Wet the cotton with water or antiseptic.You may trim the toenail one time, if needed. When trimming your toenails:Consider briefly soaking your foot in warm water to soften the nail.Use a clean, sharp trimmer.Trim toenails straight across the top. Do not taper or round the corners or trim too short. Do not try to cut out the ingrown portion of the nail yourself. This will only make the problem worse.Consider wearing sandals until the problem has gone away. Over-the-counter medications that are placed over the ingrown toenail may help some with the pain but do not treat the problem.If this does not work and the ingrown nail gets worse, see your family doctor, a foot specialist (podiatrist) or a skin specialist (dermatologist).If your ingrown nail does not heal or keeps coming back, your doctor may remove part of the nail.Numbing medicine is first injected into the toe.Using scissors, your doctor then cuts along the edge of the nail where the skin is growing over. This portion of the nail is then removed. This is called a partial nail avulsion.It will take 2 to 4 months for the nail to regrow.Sometimes your doctor will use a chemical, electrical current, or another small surgical cut to destroy or remove the area from which a new nail may grow.If the toe is infected, your doctor may prescribe antibiotics.
Expectations (prognosis)Treatment will generally control the infection and relieve pain. However, the condition is likely to return if measures to prevent it are not taken. Good foot care is important to prevent recurrence.This condition may become serious in people with diabetes, poor circulation, and nerve problems (peripheral neuropathies).
ComplicationsIn severe cases, the infection may spread through the toe and into the bone.
Calling your health care providerCall your health care provider if you:Are unable to trim an ingrown toenailHave severe pain, redness, swelling, or feverIf you have diabetes, nerve damage in the leg or foot, poor blood circulation to your foot, or an infection around the nail, your risk for complications is higher. If you have diabetes, see your health care provider.
PreventionWear shoes that fit properly. Shoes that you wear every day should have plenty of room around your toes. Shoes that you wear for walking briskly or for running should have plenty of room also, but not be too loose.When trimming your toenails:Considering briefly soaking your foot in warm water to soften the nail.Use a clean, sharp nail trimmer.Trim toenails straight across the top. Do not taper or round the corners or trim too short.Do not pick or tear at the nails.Keep the feet clean and dry. People with diabetes should have routine foot exams and nail care.
ReferencesHeidelbaugh JJ, Lee H. Management of the ingrown toenail. Am Fam Physician. 2009;79(4):303-8.Habif TP. Nail diseases. In: Habif TP, ed. Clinical Dermatology. 5th ed. St. Louis, Mo: Mosby Elsevier; 2009:chap 25.