Disorders of nails

Published on 04/03/2015 by admin

Last modified 22/04/2025

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Disorders of nails

Congenital disease

A number of usually rare congenital conditions can affect the nails. In the nail–patella syndrome, the nails (and patellae) are absent or rudimentary. The nails in pachyonychia congenita are thickened and discoloured from birth. Nail dystrophy is a feature of dystrophic epidermolysis bullosa (p. 90). Racket nails, characterized by a broad short thumbnail, is the commonest congenital nail defect. It is dominantly inherited and more common in women.

Trauma

Trauma, especially from sport, commonly causes nail abnormalities. Subungual haematomas usually occur when a fingernail has been trapped or a toenail stood on or stubbed, but the possibility of a subungual malignant melanoma must always be considered. Splinter haemorrhages are induced by trauma, although they also occur with infective endocarditis. Ill-fitting shoes contribute to ingrowing toenails, and chronic trauma predisposes to onychogryphosis – in which the big toenails become thickened and grow like a horn. Trauma may also induce onycholysis (separation of the nail from the nail bed). Constant picking of the thumbnail will produce a habit-tic dystrophy with transverse ridges and grooves. Brittle nails are a common complaint, usually due to repeated exposure to detergents and water, although iron deficiency, hypothyroidism and digital ischaemia are other causes.

Dermatoses

The nails are commonly involved in skin disease (Figs 1 and 2), and are routinely assessed in a dermatological examination. Details are given in Table 1, and a differential diagnosis of the changes is shown in Table 2. Treatment is aimed at the associated dermatosis; care of the hands (p. 38) is especially important.

Fig. 1 Psoriasis of the nails.

Pitting, onycholysis and brownish discoloration are apparent.

Fig. 2 Alopecia areata.

Thimble pitting of the nail is seen.

Table 1 Nail involvement in common dermatoses

Dermatosis	Nail changes
Alopecia areata	Fine pitting, roughness of nail surface
Darier’s disease	Longitudinal ridges, triangular nicks at distal nail edge
Eczema	Coarse pitting, transverse ridging, dystrophy, shiny nails due to rubbing
Lichen planus	Thinned nail plate, longitudinal grooves, adhesion between distal nail fold and nail bed (pterygium), complete nail loss
Psoriasis	Pitting, nail thickening, onycholysis (separation of nail from nail bed), brown discoloration, subungual hyperkeratosis

Table 2 Differential diagnosis of nail changes in dermatoses and systemic disease

Change	Description of nail	Differential diagnosis
Beau’s lines	Transverse grooves	Any severe systemic illness that affects growth of the nail matrix
Brittle nails	Nails break easily, usually at distal margin	Effect of water and detergent, iron deficiency, hypothyroidism, digital ischaemia
Colour change	Black transverse bandsBlueBlue–greenBrownBrown ‘oil stain’ patchesBrown longitudinal streakRed (’splinter haemorrhages’)White spotsWhite transverse bandsWhite/brown ‘half and half’ nailsWhite (leuconychia)YellowYellow nail syndrome (Fig. 5)	Cytotoxic drugsCyanosis, antimalarials, haematomaPseudomonas infectionFungal infection, stain from cigarette smoke, chlorpromazine, gold, Addison’s diseasePsoriasisMelanocytic naevus, malignant melanoma, Addison’s disease, racial variantInfective endocarditis, traumaTrauma to nail matrix (not calcium deficiency)Heavy metal poisoningChronic renal failureHypoalbuminaemia (e.g. associated with cirrhosis)Psoriasis, fungal infection, jaundice, tetracyclineDefective lymphatic drainage – pleural effusions may occur
Clubbing	Loss of angle between nail fold and nail plate, bulbous fingertip, nail matrix feels spongy	Respiratory: bronchial carcinoma, chronic infection, fibrosing alveolitis, asbestosis Cardiac: infective endocarditis, congenital cyanotic defects Other: inflammatory bowel disease, thyrotoxicosis, biliary cirrhosis, congenital
Koilonychia	Spoon-shaped depression of nail plate	Iron deficiency anaemia; also lichen planus and repeated exposure to detergents
Nail fold telangiectasia	Dilated capillaries and erythema at nail fold	Connective tissue disorders including systemic sclerosis, systemic lupus erythematosus, dermatomyositis
Onycholysis	Separation of nail from nail bed	Psoriasis, fungal infection, trauma, thyrotoxicosis, tetracyclines (photo-onycholysis)
Pitting	Fine or coarse pits may be seen in nail bed	Psoriasis, eczema, alopecia areata, lichen planus
Ridging	Transverse (across nail)Longitudinal (up/down)	Beau’s lines (see above), eczema, psoriasis, tic-dystrophy, chronic paronychiaLichen planus, Darier’s disease

Infections

Bacterial or fungal infection may involve the nail fold (paronychia) or the nail itself.

Onychomycosis (tinea unguium)

Fungal infection of the nails (onychomycosis) increases with age – children are seldom affected. Toenails, especially the big toenails (Fig. 3), are involved more than fingernails. The process usually begins at the distal nail edge and extends proximally to involve the whole nail. The nail separates from the nail bed (onycholysis), the nail plate becomes thickened, crumbly and yellow, and subungual hyperkeratosis occurs. Several – but almost never all – of the toenails may be involved. Tinea pedis often coexists and, if the fingernails are diseased, Trichophyton rubrum infection of the hand is usually seen. Treatment is with oral terbinafine (Lamisil) or itraconazole (Sporanox).

Fig. 3 Fungal infection of toenails.

The nails are thickened, crumbly and discoloured. An adjacent nail is not affected. Dermatophytes, C. albicans and, occasionally, moulds such as Fusarium or Scopulariopsis brevicaulis are causative.

Chronic paronychia

Chronic paronychia of the fingernails due to Candida albicans is often seen in wet workers. The cuticle is lost, the proximal nail fold becomes boggy and swollen (Fig. 4) and light pressure may extrude pus. The nail plate becomes irregular and discoloured. Gram-negative bacteria may be co-pathogens and turn the nail a blue–green colour. Management is directed towards keeping the hands dry, applying an imidazole lotion or cream to the nail fold twice daily, or oral itraconazole for 14 days.