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A-Z of Skin: Nail Disorders


The Nail Unit

Introduction
Distorted, discoloured or otherwise unsightly 'abnormal' fingernails and toenails are very common problems experienced by people of all ages in the community. Damage to the nail may be caused by an injury, fungal disease, or other skin conditions such as psoriasis or eczema.

As there are many potential conditions which cause nail abnormalities it is important for patients to seek medical advice for correct diagnosis and the most effective treatment.

Role of Nails
The nail unit is made up of several components which form, support, protect and frame the nail itself. These include the nail matrix, the nail plate, the cuticle, the nail bed and nail folds. The nail unit protects fingertips, enhances fine touch and is important as a cosmetic structure.

Some skin diseases affect all parts of the nail unit and other conditions affect only one area.

Some Conditions Causing Nail Abnormalities
Lifting of the nail plate
A normal nail is translucent and its pink colour is provided by the nail bed. The end of the nail appears white because of the air beneath it and if the nail becomes separated from the bed the white colour will extend down the nail. This condition is often a result of repeated minor injury to the underside of the nail, (for example, excessive cleaning under the free edge of the nail).



Lifting of the nail plate

Ridging of the nail
Ridging in nails can be either along (longitudinal) or across (transverse) the nail. Longitudinal ridging normally becomes more prominent with age, but can also be associated with medical conditions such as rheumatoid arthritis, lichen planus and injury to the nail.

Transverse depressions often appear some weeks after an illness or fever and grow out with the nail. Alternatively they may be caused by longstanding or severe eczema around the nail fold and also trauma from pushing back the cuticle.

Transverse layering or nail splitting
This is a frequent abnormality which involves splitting of the free end of the nail into layers. It is commonly seen in people who frequently immerse their hands in water as part of their work or home duties.

Thickening of the nail
Thickening of the nail can occur as a result of dermatological or general medical disease, and is most frequently seen in the toenails of the elderly. It often results from the long term use of ill-fitting footwear and neglect of the nails.

When psoriasis and other skin conditions affect the nail, they often lead to thickening of the nail. If a fungal infection is suspected to have caused the nail thickening a sample of the thickened nail can be collected and analysed by a laboratory. If this confirms a fungal infection specific treatments are available.

Discolouration
Medications, chemicals from hair dyes and nail varnish, nicotine and creams such as Dithranol can all cause discolouration of the nail.

Antibiotics can cause nail lifting an brownish discolouration of the nail plate. Antimalarial medications and agents used in chemotherapy may also cause discolouration. Bleeding beneath the nail plate can also cause dark discolouration.

Melanoma is another important cause of nail discolouration and may involve the nail bed, nail and/or cuticle. You should see your doctor is new or changing pigmentation of the nail or around the nail occurs.

Inflammation of the nail fold
Bacterial infection of the nail fold causes redness, swelling, tenderness and pain usually around the proximal nail fold (see diagram), sometimes with pus formation. The most common cause is bacterial infection with Staphyloccus aureus. This condition is often seen in nurses, hospitality workers and anyone involved in activities where nails are immersed in water for periods of time. Damage to the cuticle, through immersion in water or over-zealous manicuring, also predisposes to this form of inflammation.

Nail disease of traumatic origin
Nail biting is associated with infection around the nail folds and can cause deformity of the nail plate. Constant fiddling with the nails can produce longitudinal depressions along the nail. Nail cosmetics, particularly nail hardeners containing formalin, can cause separation of the nail plate from the nail bed. Adhesives used to attach artificial nails can be associated with nail and skin inflammation.

Skin with Nail Involvement
Many nail abnormalities stem from skin diseases which need to be treated to enable the nails to return to normal. Some common examples are:

Psoriasis
Psoriasis causes scaly red skin patches and visible abnormalities of the nail including pitting of the nails, with individual pits about the size of a pinhead. Psoriasis can also lead to onycholysis (lifting of the nail plate) and thickening of the nails.

Eczema/Dermatitis
This superficial inflammation of the skin causes itching, a red rash which may blister, weep and become crusted leaving the skin scaling, thickened or discoloured. Often the fingertips and surrounding skin can be affected by eczema with swelling (and possibly infection) of the nail fold tissues. This is often seen in infants who suck their thumbs.

Fungal skin and nail infections
Fungal infections of the skin ('tinea','ringworm') are contagious and may appear as itchy and occasionally painful rashes of the skin. Once the skin is infected the problem moves to nails which can be identified by thickening, a change in colour and sometimes crumbling of the nail.

'Jock itch' and 'athletes foot' are common fungal infections which can spread to other areas of the body and nails.
Diagnosis is usually confirmed by taking a sample (scraping or clipping of the nail or a sample of the debris under the nail). This sample is then examined and tested for fungal infection.

Several topical and oral treatments are available from your doctor to treat fungal nail infection. There have been significant advances in the treatment of fungal infection, and cure rates, particularly for nail infections, are much improved. All medication however can cause side effects, which are occasionally serious.

Fungal infections can be caught in many situations, but taking a few simple precautions will help avoid them. Some of these precautions are:

  • Wear thongs/sandals in communal showers
  • Dry feet and body thoroughly
  • Do not share towels and clothing
  • Wear loose fitting clothing, cotton underwear and socks
  • Wear cotton gloves under rubber gloves if hands are often in water
  • Avoid harsh or irritating soaps/detergents
  • Change shoes regularly. 'Air' them in the sun
Toenails with a fungal infection Same nails after treatment

Lumps and bumps which may affect the nail
Viral warts may occur in, around, or under the nail plate and may result in nail deformity. Cysts can occur towards the end of the finger and this can lead to a longitudinal depression in the nail. Uncommonly, skin cancers (including melanoma and squamous cell carcinoma) can occur in the nail plate area and any non-healing, growing bleeding or discoloured area should be shown to your doctor.

What if You Have a Nail Problem
If you have concerns about your nails and / or are looking for treatment, your general practitioner should be consulted for correct diagnosis of the cause and advise on the most appropriate treatment. Specialist help from a dermatologist may be required.


Acknowledgement
This information is based on a publication of the Australasian College of Dermatologists.
Last Modified 1 July, 2001 / © 2000 Australasian College of Dermatologists