Involuted toenails

What is an involuted toenail, and how common is it?

An involuted toenail is a nail that curves too much from side to side¹. The most severe form is a pincer nail (clinically, unguis constringens), where both sides curve towards each other¹². It affects roughly 1 in 100 people, most often the big toe³. Many people first notice it in adulthood, as the curve slowly increases, and it often stays painless².

It differs from an ingrown nail by its shape: a pincer nail gets narrower and higher, while an ingrown nail has a normal shape⁴.

What causes it, and who gets it?

It isn't clear yet why involuted toenails develop³. They may be inherited or acquired³⁵. Poorly fitting shoes are thought to be one of the most common causes⁴. Fungal nail infection and psoriasis are also linked with it, as are some medicines, such as beta-blockers⁵.

It can help to check that your shoes aren't narrow or pressing on your toes. Regular medicines, psoriasis, eczema, fungal nail infection or past toe injuries can all be relevant to a nail problem. Don't stop a prescribed medicine because of a nail change: discuss it with the prescriber first³⁵.

What does it feel like, and how is it diagnosed?

An involuted nail curls into the flesh without piercing the skin, usually on the big toe⁶³. It may cause no pain, even in a full tube, or severe pain². It can look red and inflamed⁶ and make walking or shoes difficult³.

A podiatrist or doctor diagnoses it from the nail's shape and an examination of your feet³⁷. Note which toes are affected, whether the nail curves in at one or both sides, and when pain started and changed. Bring a list of your medicines and health conditions.

What can I do first?

Simple care comes first. Wear wide, comfortable shoes or sandals with room at the toes⁸. Soak the foot in warm salty water, then keep it dry⁸. Keep the nail a little longer and don't trim down the sides¹. For pain, paracetamol or ibuprofen may suit you⁸.

A podiatrist can show you how to tape the nail, tuck a little cotton wool or floss under its edge⁹, or use a nail brace, which is designed to open the curve². Taping may help in mild cases if it's done correctly and consistently². Learn the technique first.

No single first-choice treatment is agreed¹⁰. Simple care is easy to do, but the problem may come back or improve only temporarily³. Check a sore toe daily for the signs to watch for.

What helps if that isn't enough?

A podiatrist can assess whether a nail brace or splint, or partial nail removal (surgery on the nail edge and root), suits you. For ingrown nails, surgery is better at stopping the nail coming back than gutter splints, and probably better than braces¹⁰. For ingrown nails, adding phenol to the nail root after nail removal seems to reduce the chance of it returning¹¹. Some experts advise trying conservative care first, because surgery can permanently change how the nail looks¹². Ask about the chance of recurrence, healing time and any risks before agreeing to a procedure.

How long does it take, and how can I stop it coming back?

A pincer nail is a long-term problem that comes and goes, and that can affect quality of life⁴. Conservative care for a pincer nail is simple, but the problem may return or only improve for a time³.

To help prevent an ingrown toenail, cut your toenails to the shape of your toe, without cutting them too short or rounding off the corners, and wear comfortable, well-fitting shoes⁹.

What can make it serious?

• An infection is getting worse, with more pain, redness, swelling or pus, but the redness isn't spreading and you feel well.
• A spot, mole or sore on the skin of your foot or leg is new, changing, bleeding or not healing.
• Redness from a wound, sore or infection is spreading into your foot or leg, or red streaks run up from it.
• You have a foot wound, ulcer or infection, or a red, hot, swollen foot, and also have a fever, chills, a fast heartbeat or feel unwell.
• Your foot, or a patch of skin on your foot or leg, becomes red, hot, swollen and painful.
• You have diabetes or poor circulation and signs of infection in your foot, toe or nail, such as redness, warmth, swelling, pus, a bad smell or more pain.
• You have diabetes, poor circulation or reduced feeling in your feet and notice a new wound, sore, blister or colour change on your foot, or a sore that isn't healing.
• You have diabetes or poor circulation and an ingrown toenail.
• You have pain in a bone with a fever.
• You have a foot wound, ulcer or infection and also feel very unwell, with confusion or slurred speech, severe shivering or muscle pain, severe breathlessness, mottled or discoloured skin, or little or no urine (possible sepsis).