Ingrown toenails

What it is

A nail edge grows into surrounding skin.

How it works

Pressure pushes the nail edge into the skin, causing inflammation and infection.

Why it matters on darker skin

Same in all skin tones.

Causes and triggers

Cutting corners, tight shoes.

What helps — and why it works

Cut straight across: prevents ingrowth. Well-fitting shoes: less pressure.

More detail

Ingrown toenails most often affect the big toe. The edge of the nail presses into the soft skin at the side, which becomes red or darker, swollen and painful, and may develop a weeping lump of granulation tissue or pus. Cutting nails too short or rounding the corners, tight or pointed shoes, sweaty feet, and injury such as stubbing the toe all contribute. Soaking the foot in warm water, keeping it clean and dry, wearing open or wide shoes and gently lifting the nail edge can help mild cases settle. Avoid cutting a 'V' into the nail or digging out the corner, which often makes it worse. If it keeps coming back, a minor procedure under local anaesthetic can remove the edge of the nail and stop that part regrowing. People with diabetes or poor circulation should see a clinician early rather than treating it at home.

What to avoid and why

Avoid digging out the corner.

Common mistakes

• Cutting too short.

Everyday nail habits

Healthy nails depend on protecting the nail matrix — the growing area hidden under the cuticle — and on limiting cycles of wetting and drying. Wear gloves for washing and cleaning, keep nails short and filed in one direction with a fine file, and moisturise hands, nails and cuticles after washing and at night. Leave the cuticle in place: it is a seal that keeps water and germs away from the matrix, and cutting it is a common cause of infection. Fingernails grow about three millimetres a month and toenails about one, so a new fingernail takes four to six months and a toenail up to eighteen months; any treatment needs at least that long to judge. Choose salons that sterilise metal tools between clients, or bring your own. Take breaks between gel or acrylic sets, and never peel coatings off. Because polish can hide important changes, look at bare nails regularly, particularly for a new dark band, a lifted nail or a change in shape.

Products and treatments

Many nail products make claims with little evidence. Moisturisers containing urea, lactic acid or petrolatum have the most support for dry, brittle nails and cracked skin around them. Formaldehyde-based hardeners can make nails more brittle over time and can cause allergy, so we do not recommend them. Antifungal nail lacquers such as amorolfine or ciclopirox can help mild fungal infection limited to the tip of one or two nails, but only after the diagnosis is confirmed — many thick or discoloured nails are not fungal at all. Biotin supplements are widely sold; evidence is weak and high doses can interfere with some blood tests. If you have diabetes or poor circulation, foot and toenail problems deserve early professional care.

Questions to ask your doctor or pharmacist

Useful questions include: What do you think is causing this? Is it likely to come back, and how can I prevent it? Which products should I stop? How long before I should expect improvement, and when should I come back if it isn't better? Are there side effects to watch for? Is this treatment safe if I am pregnant, breastfeeding or for my child? Writing your questions down, bringing your products (or photos of their labels) and taking dated photos of the problem make an appointment much more useful.