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At the heart of general practice since 1960

August 2007: Nail problems may indicate systemic disease

How can fungal or candidal nail infections be distinguished?

What causes colour change in nails?

What causes nails to ridge and thicken?

How can fungal or candidal nail infections be distinguished?

What causes colour change in nails?

What causes nails to ridge and thicken?

The nails have several important functions. They serve to protect the distal phalanges, fingertips, toes and surrounding tissue, and also enhance precise and delicate movements.

It is estimated that 45-60% of adolescents bite their nails at some time.1 For some patients nail biting may become uncontrollable, leading to deformity and infection.

The appearance of the nails can also offer fascinating clues regarding coexisting pathology. For example, leuconychia may be associated with chronic hypoalbuminaemia, and pitted onycholytic nails may be indicative of sarcoidosis and internal malignancy.

1 Onychocryptosis

Onychocryptosis (ingrowing toenails) results from an alteration in the way the nail plate fits in the nail groove, usually caused by cutting the nails incorrectly or poorly fitting footwear.

Ingrowing toenails are a common problem, resulting in pain and infection. The condition is three times more common in men than in women. All ages are affected, with incidence greatest in the second decade of life.

Sharp spicules of nail cut into the dermis of the nail groove, producing a foreign body reaction. In the first stage there is erythema, oedema and tenderness, followed by crusting and the presence of pus. In the third stage chronic infection develops, with protuberant granulation tissue that extends across the nail plate.

Treatment depends on which stage the nail has advanced to. Stage one usually requires advice about wide-fitting shoes and only cutting across the nail. Stage two requires elevation of the nail using cotton, with advice regarding rest, elevation and warm soaks. By stage three surgery is required, either to remove the nail margin or the full nail, with phenol ablation of the nail matrix.2

2 Pincer Nail

Pincer nails can be very uncomfortable. They form when the nail's convexity is exaggerated, causing the edges of the nail to turn acutely volarly, so that the nail takes the shape of an omega sign when viewed head-on at the distal phalanx.

The aetiology is not clear, but pincer nails commonly develop into ingrowing toenails as the nail cuts into the lateral perionychium, leading to infection.

This condition is often treated in the same way as an ingrowing toenail, with wedge excision of the edges of the nail or complete nail removal.

Unfortunately the nails tend to grow back in the same way, so relief is temporary. An alternative but more complex approach is the insertion of dermal grafts under the lateral edges of the nail plate. This produces excellent results and provides permanent resolution of the condition in most cases.3

3 Onycholysis

Onycholysis can be defined as spontaneous separation of the nail plate from the nail bed, starting distally and progressing proximally. It is a very common condition and has many different causes. When separation starts at the proximal end of the nail it is called onychomadesis; this is usually the result of psoriasis affecting the nail.

The condition can occur at any age.

The causes are numerous and include:

• Drugs

• Tumours

• Dermatological conditions such as atopic dermatitis

• Infections

• Trauma

• Systemic conditions such as sarcoidosis.

Treatment varies depending on the cause. In general, patients should be advised to protect the nail from trauma; limit leverage of the nail by keeping the nail short; avoid moisture, keeping nails dry with the use of gloves for washing up; and avoid exposure to irritants. If there is no infection then injection of the nail plate with a steroid may be useful.

4 Onychomycosis

Onychomycosis is one of the most common dermatological conditions, with a prevalence of 2.7% in the UK.4 Increased public awareness and newer treatments have led to more patients seeking advice for this condition.

The primary aim of treatment is to eradicate the causative organism demonstrated by microscopy or culture.

Trichophyton rubrum is the causative organism in more than 90% of cases.5 However, it is always a challenge to prove whether a detected organism is causative or a secondary colonisation of damaged tissue.

Differential diagnoses include psoriasis, trauma and candida infection.

Oral and topical treatments are available. Cure rates vary, but are often less than 50% and patients need to be warned about this before commencing treatment. Oral treatments are far more effective. Liver function tests are advised before treatment with oral terbinafine, which needs to continue for at least three months, and for up to six months for infected toenails.6

5 Paronychia

There is normally a protective barrier between the nail plate and the lateral nail folds. When this is disrupted a soft tissue infection can occur around the fingernails, which is termed paronychia.

Paronychias can be either acute or chronic, and both types should be considered as separate entities.

Acute paronychias are very common and occur as the result of damage to the nail and skin interface, usually caused by picking or trauma. The moist crevice provides an ideal environment for bacteria to breed and colonise the area, leading to pain, swelling and erythema. Treatment is with oral antibiotics, with incision and drainage if a collection of pus is present.

In chronic paronychia pain and redness may be intermittent, but the nail fold becomes thickened and chronically swollen, leading to deformity of the nails with pronounced transverse ridging. In most cases the cause is a candida infection and treatment with topical antifungals such as miconazole, or oral ketoconazole in severe cases, will be required.

6 Candida Nail Infection

Candida albicans is the main cause of chronic paronychia, but can also colonise the area between the nail plate and the nail bed. In the same process as onychomycosis secondary to fungal infection, the nails become thickened and pain may result.

Nail clippings may be required to distinguish between a fungal or yeast aetiology. In general, however, candida infection tends to produce a dark discolouration under the nail, as seen in this case.

Unlike chronic candida paronychia, where a topical antifungal may be adequate, in cases such as this, where the yeast is present in the matrix and beneath the nail, an oral preparation is required, such as ketoconazole, terbinafine or fluconazole.

7 Leuconychia

Leuconychia, paired white transverse lines across a nail, was first described by Muehrcke and signifies an abnormality of the vascular bed of the nail. Causes include:

• Severe chronic hypoalbuminaemia7

• Hodgkin's disease

• Renal failure8

• Sickle cell anaemia

• Nail damage caused by direct contact with Paraquat.

More commonly, leuconychia is caused by trauma to the proximal matrix in the area of the nail fold.

When leuconychia is associated with systemic disease the lines tend to span the entire width of the nail plate, be more homogeneous, have smooth borders and affect many nails at the same time. Trauma-induced bands are more linear and localised.

8 Median Nail Dystrophy

Median nail dystrophy is longitudinal feathered ridging in the middle surface of the nail plate.

Nails may be affected in isolation and the condition may be confused with the transverse Beau's lines, which can be associated with systemic disease or trauma.

In general, this condition is caused by habitual tic-like picking of the nail surface. It may also be seen in association with treatment with isotretinoin.9

9 Subungual Haematoma

A subungual haematoma is the result of an injury to the germinal matrix causing bleeding under the nail plate. The build-up of pressure causes the nail plate to separate from the nail bed, causing pain directly beneath the nail.

The damage to the matrix may lead to deformity of any further nail growth, which may be prevented by repairing the matrix after an injury. As a general rule, repair is not required if less than 50% of the nail is affected.

Where there is pain, drainage of the collected blood can be easily achieved by trefining a hole through the nail with a heated straightened paperclip. This can be performed without anaesthesia and provides immediate relief. Any residual haematoma will migrate distally as the nail grows over the following six to nine weeks.

Differential diagnosis includes subungual melanoma. This will not move with time, but if the diagnosis is not clear from the history then a biopsy of the nail bed may be required.

10 severe infection in a patient with diabetes

As GPs we regularly see ingrowing toenails and fungal nail infections, and advise patients how they can manage these themselves.

However, self-management is not suitable in certain patient groups. In the case shown the patient, who had diabetes, self-treated a simple ingrowing toenail. This soon developed into a severe infection with cellulitis, but the presence of a peripheral neuropathy meant that it was not painful and the severity of the condition did not become apparent for a few days.

Patients with diabetes and/or a peripheral neuropathy need to be educated about footcare and the need for caution when attempting to cut their own nails.

After the photo was taken the patient was admitted to hospital for iv antibiotics.

11 Yellow Nail Syndrome

Yellow nail syndrome is a rare condition that is usually accompanied by lymphoedema. It may be associated with pleural effusions, or less commonly with bronchiectasis, chronic bronchitis, sinus infections, internal malignancy or rheumatoid arthritis.10

All the nails may be affected and tend to grow more slowly, so that in some cases they appear to have stopped growing. As the name suggests, the nails turn yellow and become thickened and darker. Onycholysis may also occur, with surface ridging.

Once the condition is diagnosed treatment of any underlying conditions is important, although nail changes are usually permanent. Treatment with topical vitamin E solution, oral itraconazole and zinc supplements have been used, but the mechanism of action is unclear.11

12 Onychogryphosis

Onychogryphotic nails, also referred to as ram's horn nails, are very thickened and deformed. They usually occur as a result of trauma or neglect.

Once the nail becomes excessively thickened cutting becomes impossible and referral to a podiatrist is usually required to grind down the nails.

This process needs to be ongoing in many cases, the only alternatives being removal of the nail and ablation of the nail bed or complete matricectomy to prevent regrowth.

Author

Dr Nigel Stollery
MB BS
GP, Kibworth, Leicestershire and clinical assistant in dermatology, Leicester Royal Infirmary

Ingrowing toenails are usually caused by incorrect cutting or poorly fitting footwear Figure 1: Ingrowing toenail Pincer nails are treated with excision of the edges of the nail or complete nail removal. The nails tend to grow back in the same way, so relief is often temporary Figure 2: Pincer nail Onycholysis. Patients should be advised to protect the nail from trauma, keep the nail short and avoid moisture and exposure to irritants Figure 3: Onycholysis Onychomycosis. Cure rates vary, but are often less than 50% Figure 4: Onychomycosis Paronychia is a soft tissue infection occurring at a disruption of the protective barrier between the nail plate and lateral nail fold Figure 5: Paronychia Candida nail infections tend to produce a dark discolouration under the nail Figure 6: Candida nail infection Leuconychia, paired white transverse lines across a nail, signifies an abnormality of the vascular bed of the nail Figure 7: Leuconychia Median nail dystrophy. In general, this condition is caused by tic-like picking of the nail surface Figure 8: Median nail dystrophy Subungual haematoma. Trefining a hole through the nail with a heated straightened paperclip can provide immediate pain relief Figure 9: Subungual haematoma Patients with diabetes and/or a peripheral neuropathy should be educated about footcare and the need for caution when cutting their own nails Figure 10: Severe infection in a patient with diabetes Yellow nail syndrome is usually accompanied by lymphoedema Figure 11: Yellow nail syndrome Onychogryphosis usually occurs as a result of trauma or neglect. Referral to a podiatrist is usually required Figure 12: Onychogryphosis

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