Nail abnormalities: a visual guide

Nail abnormalities can tell you a lot about your general health. Use this guide to understand what changes in the appearance of a nail can mean and when you should see your GP.

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Pitted nails

Pitting on the surface of the fingernails may be a sign of any of the following conditions:

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Discoloured nails

A nail with a fungal infection can look ugly, as the nail often thickens and can turn white, black, yellow or green. The nail can sometimes become brittle, with pieces of nail breaking off or even coming away from the toe or finger completely.

The nail bed may also become inflamed and painful, but this tends to suggest a yeast infection rather than a fungal one.

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Ram's-horn nails

Ram's horn nails (onychogryphosis) is a nail disorder that's more common in older people. It's possible for nails to become so overgrown, that they're very difficult to cut with conventional nail clippers.

Soaking the nails in water before cutting or regular chiropody can help, but sometimes the nails need to be removed by a podiatrist or doctor.

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Spoon-shaped nails

Fingernails that curve inwards like spoons (koilonychia) can be perfectly normal in children but may be a sign of an underlying medical condition in adults. For example:

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Grooves on the nails

Illness, injury or cold temperatures can stop nail growth and cause deep lines or grooves to form across the base of the nails (Beau's lines). These may only be noticed when the lines have grown up the nail.

It takes about six months for a fingernail to fully grow out and 6-12 months for a toenail.

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Unusually curved fingertips

Clubbing of the fingertips can run in families and be entirely harmless. However, if it suddenly develops, it may be a sign of one of many underlying medical conditions, including:

With clubbed fingertips, the fingernails curve over the top of the fingers. Normal nails should dip downwards towards the cuticle, creating a natural angle.

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Dark stripes

If you have dark skin, it's fairly common to have streaks of the pigment melanin down your fingernails.

However, it's still important to get them checked by a doctor, as dark stripes may sometimes be a form of skin cancer called subungual melanoma (shown in the picture).

Subungual melanoma usually only affects one nail, causing the stripe to change in appearance (for example, it may become wider or darker over time). The pigmentation may also affect the surrounding skin.

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Little brown streaks

Little brown or red streaks under the fingernail are usually splinter haemorrhages. These are lines of blood caused by tiny damaged blood vessels. Just a few splinters under one nail is nothing to worry about and is most likely due to the nail being injured.

However, if a few nails are affected, these splinters may be a sign of another condition, such as:

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Splitting of the finger nails

Brittle nails that easily split could just be a sign of ageing or may be caused by long-term exposure to water, or chemicals such as detergents and nail polish.

It may help to wear gloves to protect your hands in water, regularly moisturising the nails, and reducing the use of nail varnish and nail varnish remover.

Sometimes, brittle nails may be caused by:

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Vertical ridging

Vertical ridging is usually caused by ageing and can be compared to wrinkles developing on your skin.

The ridges run from the nail bed to the tip and generally start in one or two nails. Over time, the ridges can appear on all nails. Gentle filing and buffing may help to smooth them.

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Nail lifting

Nail lifting (distal onycholysis) happens when the tip of the nail separates from the nail bed on the finger or toe.

It can be the result of psoriasis or a fungal disease, but is often due to overzealous manicures or cleaning under nails with sharp objects. The space under the nail can then become filled with bacteria, which turn the nail greenish-black.

Nail lifting can be treated by soaking the nail in diluted white vinegar or bottle sterilising solution containing sodium hypochlorite.

In the long-term, keeping the nails short will help to reduce any further trauma and allow the nail to grow out attached. Use a soft nailbrush to clean your nails, don't clean under the nails where they meet the fingernail and avoid using sharp objects to clean under your nails.

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Longitudinal grooves

Longitudinal grooves usually run along the nail, from base to tip and are often caused by a digital myxoid cyst pressing on the nail matrix (where the nail is made).

A digital myxoid cyst is thought to be the result of wear and tear in the joint at the fingertip. It's completely harmless and doesn't need treatment, unless it causes symptoms.

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NHS Choices 2016

Nail abnormalities: a visual guide - Health tools - NHS Choices