Discolouration of the nails

Contributed by Dr Jean Watkins, a retired GP in Hampshire.

Nicotine staining

At first glance, it was obvious that this patient was a smoker. She had been smoking for 40 years and was currently on 60 a day. Such awareness may give us insight into the patient's symptoms or the opportunity to offer nicotine replacement therapy (NRT), bupropion or varenicline, and the chance for her to attend a smoking cessation programme. The patient agreed to set a target date for stopping smoking. A prescription was offered for an initial two weeks.

Subungual haematoma (differential diagnosis)

This man had noticed changes under the nail of his big toe for over two months. He first noticed a small discoloured area under the nail but it had gradually increased in size and now the nail over the lesion was cracked. There was concern that this could be a malignant melanoma (MM) and he was referred for biopsy, which returned histological confirmation of a subungual haematoma. MM may present with pigmentation or streaking under the nail but is also associated with pigmentation of the nail folds (Hutchinson's sign).

Fungal nail infections - moulds

This woman, a keen gardener, presented with a thickened discoloured nail. It was a longstanding problem that had bothered her for over 10 years. The tip of her finger was swollen and tender. Nail clippings identified fusarium species as the cause. Twice the nail had been removed but the problem had recurred as the nail regrew. A course of itraconazole had not helped the situation. Fusarium is present on plants and in the soil, but does not commonly affect the nail. It is not a serious problem unless the patient is immunocompromised. It may then be invasive and fatal.


Onychogryphosis is a condition in which the nail becomes discoloured, thickened and distorted, as it becomes elongated and curved - like a ram's horn. It occurs as a result of trauma which may be sudden, from a fallen object, or gradual from 'banging' the toes against the toes of the shoes. The big toe is most commonly affected. Problems arise when the nail is too thick for the patient to cut and the nail continues to grow. The chiropodist may be able to keep the problem at bay for a while but final relief may come only with removal of the nail under local anaesthetic.

Subungual haematoma

This woman had shut her finger in a car door three weeks earlier and she seemed to be losing the nail. Following such an injury, it is generally recommended that medical help should be sought if the haematoma covers more than 25 per cent of the nail area. Drainage of the haematoma may quickly help to relieve the pain by perforating the nail, either by cautery, or penetration with a large bore needle under a local anaesthetic digital block.

Fungal nail infections - Tinea unguium

Tinea unguium is due to a dermatophyte such as tinea rubrum or tinea interdigitale. The big toe is most frequently affected. The side of the nail is usually first affected and turns yellow, brown or black. Later the nail becomes thickened and crumbly. This patient had noticed the changes for about a year. A diagnosis of MM was unlikely. Nail clippings were taken from under the nail. Trichophyton rubrum was confirmed to be the cause. A topical antifungal preparation can be tried but oral antifungal therapy for several months is required for a successful outcome.

Pseudomonas infections

Pseudomonas species affect diseased nails and nails affected with this problem will look a distinctive green colour that should suggest the diagnosis. Sometimes affected nails will be black or blue. Pseudomonas pyocyanea is present in tap water and so this infection is likely to occur in patients who frequently immerse their hands in water. Patients should be advised to keep their hands as dry as possible and to wear cotton-lined rubber gloves at work and for daily household chores. The infection will respond to the application to the nail bed of 30 per cent sulphacetamide eyedrops in 50 pre cent spirit.

Yellow nail syndrome

Yellow nail syndrome is sometimes seen in middle-aged patients. The nails are yellow, dystrophic and slow growing but may be smooth or cross ridged. It is related to deficient lymphatic drainage usually of the lower limbs. This patient had longstanding, severe lymphoedema of the legs. It may be associated with recurrent pleural effusions. Once the nail changes have occurred they are usually permanent. Apart from treatment of the underlying causes, occasionally reversion to normal may occur with the help of topical vitamin E solution and oral itraconazole or fluconazole.

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