Chapter 127: Nail disorders

Making a diagnosis of abnormal nails for a concerned patient can be quite simple for a few obvious conditions. However, in many cases the diagnosis can be elusive when we are not familiar with classic patterns that are seen so infrequently. The diagnostic process can be facilitated by learning the basic anatomy and function of the nail, as well as characteristic patterns, which are presented with the aid of diagrams in this chapter. There are, in fact, only a limited number of ways in which injury, infection and inflammation can present in a nail.¹

The main nail problems encountered in general practice are trauma, onychomycosis, infection, ingrowing toenails, paronychia and psoriasis. Fungal nail infection and psoriasis are the commonest causes of nail dystrophy. Damage to the nail from trauma or disease results in nail dystrophy. The problem of nail changes due to onychotillomania, be it from excessive nail biting, picking or cleaning, should be suspected from the history and examination.

The examination should include a general inspection of the skin including in the webbing of the toes, looking for evidence of a skin disorder such as psoriasis, atopic eczema, lichen planus and tinea.

A summary of causes of abnormal nails is presented in TABLE 127.1.

Key history

Enquire about a history of severe stress or illness and possible onychotillomania, be it excessive nail biting, picking or cleaning. Ask whether the hands are frequently in wet work (e.g. dishwashing, soaps and detergents) or dirt.

Key examination

Careful examination of nails: look for associated skin disease (e.g. psoriasis, atopic dermatitis, tinea pedis, lichen planus).

Key investigations

• Nail clippings for culture and histology

• FBE and ESR

• Consider LFTs

The basic nail unit (apparatus) consists of the nail matrix, the proximal and lateral nail folds, the cuticle and the nail plate (see FIG. 127.1). The hard keratin of the nail plate is formed in the nail matrix. The matrix, which contains germinal epithelium, lies in an invagination of the epidermis (the nail fold) and is protected by a waterproof seal formed by the cuticle. The matrix runs from the proximal end of the nail fold to the cuticle.

The nail bed closely approximates the distal phalanx. The nail has an important functional and cosmetic role. It enhances fine touch and motor skills for picking up fine objects, such as a pin from a flat surface, not possible without fingernails.

Lifting of the nail plate (onycholysis)

See FIGURE 127.2.

Causes

• Trauma

• Factitious (self-induced)

• Tinea

• Psoriasis

• Photosensitivity, usually tetracyclines

• Others (e.g. warts, lichen planus)

• Hyperthyroidism

• Nail destruction:

  • – squamous cell carcinoma

  • – melanoma

  • – lichen planus

Thickening of the nail plate

Causes

• Developmental

• Trauma

• Tinea

• Psoriasis (see FIG. 127.3)

• Onychogryphosis

• Age-related changes

Thinning of the nail plate

Causes

• Trauma—wear and tear (repeated water immersion)

• Artificial fingernails—application and removal

• Lichen planus

• Peripheral vascular disease (impaired peripheral circulation)

• Twenty-nail dystrophy, usually children

• Brittle nails

Pitting of the nail plate

See FIGURE 127.4.

Causes

• Psoriasis

• Alopecia areata

• Atopic dermatitis

Longitudinal marks in the nail plate

See FIGURE 127.5.

Causes (grooved)

• Myxoid cyst

• Angiofibroma

• Ageing

Causes (central single stripe)

• Darier disease

• Hereditary/congenital

• Mechanical trauma

Horizontal grooves in nail plate

Causes

• Beau’s lines (from acute illness) (see FIG. 127.6)

• Habit tic (picking cuticle of thumb nail) (see FIG. 127.7)

• Atopic dermatitis

• Raynaud phenomenon

Horizontal single white lines or band

Causes

• Chemotherapy

• Arsenic poisoning

• Kidney failure

Lamellar splitting (onychoschizia)

See FIGURE 127.8.

Causes

• Trauma—repeated wetting and drying (e.g. housework)

Abnormal curvature

Causes

Spoon nails: koilonychia

See FIGURE 127.9.

• Idiopathic (most cases, esp children)

• Hereditary

• Trauma

• Iron deficiency

• Haemochromatosis

Overcurvature

• Hereditary pincer nail

Clubbing

See FIGURE 127.10.

• Hereditary/congenital

• Lung disease (e.g. cancer, pulmonary fibrosis, sepsis)

• Heart disease (e.g. congenital cyanotic, SBE)

• Liver disease (e.g. cirrhosis)

• Gastrointestinal disorders (e.g. Crohn disease)

Splinter haemorrhages

See FIGURE 127.11.

Causes

• Minor trauma (e.g. manual workers)

• Bacterial endocarditis

Discolouration of the nail plate

• White:

  • – striate leuconychia (usually trauma)

  • – liver cirrhosis

  • – hypoalbuminaemia (total whiteout)

• Red:

  • – splinter haemorrhages

  • – kidney failure

  • – polycythaemia

  • – CO poisoning

  • – glomus tumour

• Brown:

  • – fungal infection

  • – cigarette staining

  • – drugs—gold, chlorpromazine

  • – Addison disease

  • – psoriasis (‘oil stain’ patches)

  • – melanoma

• Black:

  • – haematoma

  • – melanoma

  • – racial pigmentation

  • – naevus

  • – minocycline

  • – cytotoxic drugs (transverse bands)

• Green:

  • – Pseudomonas infection

  • – Aspergillus infection

• Blue:

  • – antimalarials

  • – argyria

• Yellow:

  • – yellow nail dystrophy (? respiratory illness)

  • – fungal infections

  • – psoriasis

  • – slow growth

  • – tetracyclines

• Half (pale proximal) and half (brown or red distal) (i.e. half-and-half nails)

  • – kidney failure (chronic)

  • – liver cirrhosis

  • – trauma (biting, splits, splinters)

Swelling of the proximal nail folds (paronychia)

• Trauma (e.g. biting)

• Manicure (retracting the cuticles)

• Candida infection

• Staphylococcal infection

• Herpetic whitlow

Swelling of the lateral nail folds

• Ingrowing toenails

• Retinoids

• Overcurvature of the nail plate

Tumours of the nail fold

Benign:

• myxoid (mucus) cyst

• warts

• periungual fibroma

Malignant:

• squamous cell carcinoma

• melanoma

Destruction of the nail apparatus

• Trauma

• Lichen planus

• Melanoma

• Bowen disease

• Squamous cell carcinoma

Onycholysis¹

Onycholysis refers to the separation of the nail plate from the underlying nail bed and is a sign rather than a disease. This separation creates a subungual space with an air interface that gathers unwanted debris, such as dirt and keratin. It is usually seen in fingernails but it can develop in toenails from rubbing against shoes. Adverse local reactions to agents such as formaldehyde and resins in polishes or nail glues can distort nails.

Self-induced trauma is a common cause from obsessive manipulation, including meticulous cleaning and frequent manicuring.

The band of discolouration at the end of the separated nail is usually in a straight line compared with other causes such as psoriasis and tinea. Tinea may be distinguished from other causes by white or yellow streaks or ‘spears’ travelling proximally in the nail.

Greenish discolouration indicates invasion by Pseudomonas pyocyanea or Aspergillus.

Management⁵

First exclude psoriasis, tinea (check toe webbing) and trauma (check history).

Fingernails

• Keep nails as short as possible

• Avoid insertion of sharp objects under nails for cleaning out debris

• Apply tape (Micropore or similar) over free edge for months, until healed

• Avoid unnecessary soaps and detergents—wear gloves for housework, gardening, etc.

• Keep hands out of water

• Use a mild soap and shampoo

• First-line treatment especially if mild infection is white vinegar soaks, diluted 1:1 with water—10 minutes two times daily for 3–4 weeks.⁶

Toenails

• Exclude fungal infection (clinical tinea pedis)—culture

• Improve footwear to avoid any rubbing

Pharmaceutical treatment

• Daily application of an imidazole (e.g. clotrimazole) or terbinafine

• Potent topical corticosteroids in lotion form may be useful

• For Pseudomonas infection soak the nails in vinegar or Milton’s solution and/or gentamicin sulphate cream

• If Candida albicans confirmed, best to use oral treatment, e.g. fluconazole or itraconazole⁶

Refer difficult and unresponsive cases to a dermatologist.

Psoriasis of nails

Psoriasis can have many manifestations, such as pitting, onycholysis, discolouration, splinter haemorrhages, distal subungual hyperkeratosis (which can resemble warts) and severe total nail dystrophy (often with arthropathy). Psoriasis can closely mimic onychomycosis, which should be excluded by fungal culture and histology before commencing presumed tinea therapy.

There is no effective topical therapy for psoriasis of the nails but a trial of a potent corticosteroid lotion may help selected cases. Intralesional steroid injections, which are painful and require multiple treatments, can help. Successful treatment of the skin does not help the nails.

Onychomycosis (fungal nail infection)

Treatment^5,6

In most cases it is not a major clinical problem and no treatment is a reasonable plan. Regular nail clipping is important. The antifungal treatment of choice for all types of toenail tinea is:

• terbinafine 250 mg (o) daily for 12 weeks (cures 70–80% of cases); 6 weeks for fingernails

An alternative is itraconazole 200 mg (o) bd for the first week of each month for 2 months for fingernails; 3–4 months for toenails.

Tips

No improvement apart from the proximal part of the nail will be noticed after months because it takes 12 months or more for the toenail to grow.

Mark the base of the dystrophic nail with a scalpel blade or black ink to assess progress.

Topical treatment for superficial or distal nail involvement⁷

• amorolfine 5% (Loceryl) nail lacquer 1–2 times weekly after filing (fingernails: 6 months; toenails: 9–12 months)

• or

• miconazole tincture daily until resolution

• or

• ciclopirox lacquer daily until resolution

A systematic review found poor evidence for the effectiveness of topical therapy for onychomycosis.⁸

Consider twice-daily applications of tea-tree oil indefinitely for tinea pedis and tinea unguium.

Acute paronychia

This is a painful condition that is mainly due to bacterial infection, especially Staphylococcus aureus.

Management

Uncomplicated with localised pus:

• simple elevation of nail fold or puncture the fold—close to drain pus

• advice on hygiene

• antibiotics not usually necessary

• if not responding to drainage, use (di)flucloxacillin

• exclude diabetes

Complicated with subungual extension:

• small vertical incision alongside the nail, or

• removal of nail in part or totally

• exclude diabetes

Chronic paronychia

Clinical features

• Painless

• A form of traumatic nail dystrophy

• Loss of cuticle fundamental to diagnosis

Causes

• Excessive manipulation of cuticles (e.g. by manicurists)

• Occupational (e.g. chefs, housewives, nurses, fishmongers)

• Frequent contact with water, detergents and chemicals

• Habit tic—picking the nail fold

Note:

• Secondary infection with Candida common but not basic cause.

• The damaged cuticle permits access of water and grit to the nail matrix and causes inflammation of the proximal nail fold.

Management^4,5

• Culture organisms

• Exclude diabetes

• Basic nail care advice:

  • – keep hands dry (avoid wet work if possible)

  • – wear cotton-lined gloves when washing dishes (for max. of 15 minutes)

  • – minimise contact with water, soap, detergents, lipid solvents and other irritants

  • – never pick, push back or manicure cuticles

  • – never insert anything beneath cuticle for cleaning

  • – wear cotton gloves in garden

  • – use a mild soap and shampoo

Medications⁵

For Candida (if cultured):

• tincture miconazole 2% bd for 7 days

• or

• clotrimazole topical preparations

For Staphylococcus (if cultured):

• Bactroban topical ointment

Topical medications to nail folds (especially if persistent exudate):

• 4% thymol in alcohol (SVR) qid

• or

• 10% sulphacetamide in alcohol

Vaseline (to waterproof) can be applied frequently (5–10 times daily) when it is dry and without exudate.

Very potent topical corticosteroids are helpful. Refer unresponsive cases.

• Avoid irritants: special soaps, wear gloves for dishwashing

• Good nail hygiene

• Apply potent topical steroids to proximal nail fold

This commonly presents in the nail with atrophy of one or more nails. The nail plate is predisposed to breaking and splitting as it thins. If advanced, a pterygium arising from the proximal nail fold grows as the nail matrix is destroyed and eventually total loss of the nail may occur.

Biopsy of the nail matrix is recommended before treatment.

Intralesional steroids into the proximal nail fold are the treatment of choice if seen prior to destruction of the nail unit. Otherwise a trial of prednisolone 25 mg (o) daily for 4 weeks, reducing the dose gradually over 1–2 weeks, may induce temporary remission.

Twenty-nail dystrophy

This is an uncommon disorder seen in preschool or pre-adolescent children with thinning and roughening of all or almost all 20 nails. It may be a prodrome to psoriasis, lichen planus or alopecia areata but it tends to be a self-limiting condition and most cases resolves over 2–3 years.⁴

It is reported to respond well to the very potent topical steroid, clobetasol.

Brittle nails

The nails break easily, usually at their distal end. Brittle nails are age related and are usually caused by local physical factors, such as repeated water immersion, and exposure to chemicals, such as detergents, alkalis and nail polish removers and also hypothyroidism and digital ischaemia. Systemic causes such as deficiency of iron and vitamins are not considered to be a common factor.

Calcium does not contribute to the hardness of nails and calcium deficiency does not cause brittle nails.⁴ No cosmetic applications appear to be helpful.

Management⁴

• Avoid excessive hydration and trauma

• Wear rubber gloves with cotton liners for wet work

• Massage Vaseline or nail creams (e.g. Eulactol or NeoStrata) into the nail several times daily

• Nail polishes and hardeners (preferably without formalin) may give a good cosmetic result

Nail apparatus melanoma

Clinical features⁵

• Rare but potentially fatal

• Responsible for 2–3% of all melanomas

• All age groups but especially in seventh decade

• Affects all ethnic groups in all climates

• Presents as a longitudinal pigmented streak in the nail (see FIG. 127.12)

• Hutchinson sign (pigmentation of the proximal nail fold) may be present

• Usually diagnosed late

• Mortality >50%

• Median survival <12 months after diagnosis

• Early recognition and referral may result in a cure

Management

• All cases require a longitudinal nail biopsy for diagnosis

• If confirmed, treatment is based on Breslow thickness and level of invasion

• Level 1 or in situ—removal of whole nail apparatus

• Invasive melanoma—amputation of distal phalanx

Glomus tumours

Glomus tumours are those mysterious little tumours that occur beneath the nail plate and can give paroxysms of sharp pain.

They are small purplish lesions that are exquisitely tender to touch and activate with changes in temperature. They may not be visible but may be revealed when the nail bed is blanched with gentle pressure. Imaging may be needed for diagnosis. Treatment is surgical.

Onychogryphosis

Onychogryphosis, or irregular thickening and overgrowth of the nail, is commonly seen in the big toenails of the elderly and appears to be related to pressure from footwear (see FIG. 127.13). It is really a permanent condition. Simple removal of the nail by avulsion is followed by recurrence some months later. Softening and burring of the nail gives only temporary relief, although burring sometimes provides a good result.

The powder from burring can be used as culture for fungal organisms. Permanent cure requires ablation of the nail bed after removal of nail.

Two methods of nail ablation are:⁶

1. total surgical excision

2. cauterisation with phenol (with care)

Refer to section in CHAPTER 68.

Periungual warts

These are similar to other warts and fortunately rarely spread under the nail to the nail bed. Caution is needed with treatment.

Cryotherapy must be used with caution to avoid damage to the nail matrix—otherwise it is usually safe but often ineffective. Consider wart paints under occlusion.

The small, localised haematoma

There are several methods of decompressing a small localised haematoma under the fingernail or toenail that causes considerable pain. The objective is to release the blood by drilling a hole in the overlying nail with a hot wire or a drill/needle.

Treatment

Method 1: the sterile needle

Simply drill a hole by twisting a standard disposable hypodermic needle (21 or 23 gauge) into the selected site. Some practitioners prefer drilling two holes to facilitate the release of blood.

Method 2: the hot paper clip

Take a standard, large paper clip and straighten it. Heat one end (until it is red hot) in the flame of a spirit lamp. Immediately transfer the hot wire to the nail, and press the point lightly on the nail at the centre of the haematoma. After a small puff of smoke, an acrid odour and a spurt of blood, the patient will experience immediate relief (see FIG. 127.14).

Method 3: electrocautery

This is the best method. Simply apply the hot wire of the electrocautery unit to the selected site (see FIG. 127.15). It is very important to keep the wire hot at all times and to be prepared to withdraw it quickly, as soon as the nail is pierced. It should be painless.

Important precautions

• Reassure patients that the process will not cause pain; they may be alarmed by the preparations.

• The hot point must quickly penetrate, so go no deeper than the nail. The blood under the nail insulates the underlying tissues from the heat and, therefore, from pain.

• The procedure is effective for a recent traumatic haematoma under tension. Do not attempt this procedure on an old, dried haematoma as it will be painful and ineffective.

• Advise the patient to clean the nail with spirit or an antiseptic and cover with an adhesive strip to prevent contamination and infection.

• Advise the patient that the nail will eventually separate and a normal nail will appear in 6–9 months.

The large haematoma

Where blood occupies the total nail area, a relatively large laceration is present in the nail bed.

Treatment

To permit a good, long-term functional and cosmetic result it is imperative to remove the nail and repair the laceration (see FIG. 127.16).

Method

• Apply digital nerve block to the digit.

• Remove the nail.

• Repair the laceration with 4/0 plain catgut.

• Replace the fingernail, which acts as a splint, and hold this in place with a suture for 10 days.

Myxoid pseudocyst

There are two types of digital myxoid pseudocysts (also known as mucous cysts) appearing in relation to the distal phalanx and nail in either fingers or toes (more common) (see FIG. 127.17). One type occurs in relation to, and often connecting with, the distal interphalangeal joint and the other occurs at the site of the proximal nail fold. The latter (more common) is translucent and fluctuant, and contains thick clear gelatinous fluid, which is easily expressed after puncture of the cyst with a sterile needle. Osteoarthritis of the DIP is associated with leakage of myxoid fluid into the surrounding tissue to form the cyst.

Some pseudocysts resolve spontaneously. If persistent and symptomatic attempt:⁹

• repeated aspiration (aseptically) at 4–6 weekly intervals

• or

• cryosurgery

• or

• puncture, compression, then infiltration intralesionally with triamcinolone acetonide (or similar steroid)

They tend to persist and recur; if so, refer to surgery for total excision of the proximal nail fold and/or ligation of the communicating stalk to the DIP or (preferably) microscopic dissection to the capsule defect and capsule repair.

Hand-out sheets from Murtagh’s Patient Education 7th edition:

• Nail disorders