Fingernail or toenail abnormalities can tell you a lot about your health. They’re often a sign of a fungal nail infection or injury but can sometimes indicate a more serious underlying disease.

Brittle nails are often just a sign of ageing or long-term exposure to water or chemicals such as nail polish and detergents.

Sometimes, brittle or crumbly nails can be caused by:

  • A fungal nail infection
  • A skin condition called lichen planus
  • Nail psoriasis. This is a long-term skin condition that can cause the nails to become crumbly
  • A less common cause of crumbly nails is reactive arthritis. This is an unusual reaction of the immune system affecting the joints, muscles and other parts of the body following an infection.

Fungal nail infections

Fungal infections of the nails are also known as dermatophytic onychomycosis, or tinea unguium. The fungus responsible is usually the same as the one that causes athletes foot. Athletes foot is a common fungal infection of the skin of the feet, most prominent between the toes. The fungus of athletes’ foot lives in the keratin which makes up the outer layer of the skin. When this fungus spreads to the keratin of the nails, this then results in a nail fungus infection.

What causes fungal infections?

Fungi spreading from athletes’ foot causes most fungal nail infections. Although it can also be caused by yeast and mould. These other fungi attack the nails that are already damaged as it is easier for the fungus to invade.

Fungal nail infections, especially of the toenails are extremely common, with 80% of the population contracting one at some point in their lives. The most common group associated with fungal nail infections are the elderly, those with impaired immune systems, and those that suffer from diabetes – due to the fact they are more susceptible to infections.

Are they hereditary?

No, but those living together may suffer from fungal infections at the same time because they can transfer from person-to-person.

What are the symptoms of a fungal nail infection?

Usually there are no symptoms at the start of the fungi, but later the nails may become so thick that they hurt when they are pressed on the inside of a shoe. They will also be hard to trim.

The nail can become unsightly through discolouration and cracks. The skin near to a nail infection may also itch, crack or appear white, especially between the toes.

What do fungal nail infections look like?

Fungal Nail Infection When a nail is first infected, the fungi usually starts at the edge of the nail and spreads down the side of the nail towards the base of the cuticle. Eventually the whole nail may become infected.

The infected areas usually turn white or yellowish, and become thickened and crumbly. In some cases, there may be white areas on the nails surface. The nails most commonly affected by a fungal nail infection are those on the big and little toes.

How are fungal nail infections diagnosed?

Many nail problems can appear to look like a fungal infection, such as psoriasis of the nails, bacterial infections, or an old injury, however anti-fungal tablets will not help them.

In order to treat a fungal nail infection a dermatologist will take a piece from a crumbly area of your nail and send it to be checked for fungus. The right treatment will depend on what fungus is present from test results.

Lichen Planus

Lichen Planus is a non-infectious, itchy rash that can affect many areas of the body. Affected areas can include, the arms and legs, mouth, nails and scalp.

What does lichen planus look like?

Lichen planus of the skin often affects the wrists, ankles and lower back, although other parts of the body can also be affected. Thickened (hypertrophic) lichen planus affects the shins and ring-shaped lichen planus affects creases in the skin, such as the armpits. After the lesions have cleared, the affected area of skin can sometimes become discoloured.

How do you treat lichen planus?

There is no single cure for lichen planus completely, however there are treatments available to help manage the symptoms. The most common treatment used is steroid creams which helps to relieve the itch and control the rash.

Who is affected by lichen planus?

An estimated 1-2% of the population worldwide is affected by lichen planus and is most common in adults aged over 40.

Psoriasis of the nails

Psoriasis can affect both the finger and toenails. Psoriasis is a common condition that causes inflammation of the skin. It usually develops as patches of red scaly skin.

What are the symptoms of nail psoriasis?

  • Pitting of the nails – small pits can appear on the surface of the nail. There may be one pit or many on the surface of a single nail.
  • Onycholysis – this is where the nail separates from the skin underneath the nail. At first this looks like a white or yellow patch at the tip of the nail. This patch will gradually increase in size and reach the base of the nail. The gap between the nail and skin underneath can become infected and change colour.
  • Subungual hyperkeratosis – this is where a chalk-like material builds up under the nail. The nail will become raised and often tender to touch.
  • The colour of the nail may change, such as turning to a yellow brown.
  • Fungal nail infections can occur with psoriatic nail disease. Fungal nail infections can cause thickening of the nails.

How common is psoriasis of the nails?

About 1 in 50 people have psoriasis at some time in their lifetime. It can develop at any age, but most often starts between the ages of 15-30.

Nail changes occur in about half of those suffering with psoriasis. Only a few people have psoriatic nail disease without having psoriasis affecting their skin.

What treatment is available for psoriatic nail disease?

Mild nail disease which isn’t causing discomfort does not usually need treatment. If nail disease is severe and causing problems, then you should seek specialist advice and treatment. Treatment may include, steroid creams, anti-fungal treatment, light therapy and salicylic acid.