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NAIL CHANGES ASSOCIATED WITH DERMATOSES,SYNDROMES OR SYSTEMIC DISEASE

Practice points

Psoriasis

Psoriasis of the nail may manifest itself as nail plate pitting, onycholysis (Fig.29.23), ‘oil spots', a salmon pink-colored area subungually, or as nail bed thickening (see Ch.7). Psoriasis of the matrix results in nail surface pits; the other changes are due to nail bed involvement. Treatment should take into account the location of involvement. Distal subungual nail bed psoriasis may respond nicely to an alcohol-based steroid liquid (e.g. clobetasol) dripped under the nail twice daily. Intralesional triamcinolone (2.5mg/mL) to the proximal nail fold is a painful procedure but can be quite effective for psoriasis of the nail matrix. Soak PUVA may be effective. Systemic therapy (e.g. methotrexate and systemic PUVA) may clear all forms of nail psoriasis, but these therapies are not generally indicated for nail disease alone.

Figure 29.23 Onycholysis from psoriasis. Psoriasis of the nails can lead to pits, ‘oil spots’, or onycholysis.

Lichen planus

Nail involvement in lichen planus may take many forms, including longitudinal ridging (Fig.29.24), thinning, onycholysis, and pterygium formation. Nail matrix biopsy may be necessary for diagnosis. Pterygium is a term used to describe adhesion of the proximal nail plate to the matrix. The nail may be absent or significantly thinned. Pterygium has also been reported to occur in sarcoidosis (see Ch.11).

Low-dose prednisone (e.g. 0.5mg/kg every other day), intramuscular triamcinolone, intralesional triamcinolone, or acitretin have been used. Aggressive treatment may be justified to prevent permanent scarring.

Figure 29.24 Lichen planus. Longitudinal ridging is seen on the fourth fingernail. Atrophy with the beginning of pterygium is seen on the fifth fingernail.

Darier disease

Nails in patients with Darier disease often have red and white longitudinal lines as well as distal V-shaped nicks (Fig. 29.25; see Ch.19).

Figure 29.25 Darier disease. This shows typical longitudinal white streaks and notched splitting of the free margin of the nail.

Beau lines

Transverse furrows or ridges of the nail plate that develop after various diseases or chemotherapy are called Beau lines (Fig.29.26). They are caused by temporary arrest of nail growth. Minor versions may just cause a transverse band of pallor. They are most commonly noticed in fingernails, but toenails are equally affected. Unilateral Beau lines have occurred in association with reflex sympathetic dystrophy.

These lines will grow out, and eventually the ridge will be clipped off to leave a normal nail plate; this takes about 6 months in fingernails, and it is possible to give quite a good estimate of when the patient was ill from the position of the transverse ridge.

A severe insult may result in loss of the nail (onychomadesis, Fig.29.27).

Figure 29.26 Beau lines. The patient had infectious mononucleosis 4 months earlier.

Figure 29.27 Onychomadesis. A severe transverse groove may result in complete loss of the nail, termed onychomadesis. This case was secondary to azathioprine treatment in a patient with pemphigoid.

Terry nails

The distal 1–2-mm rim of the nail (which is still in contact with the nail bed) is pink, while the rest of the nail is white. This appears to be a non-specific sign, although in the patient shown in Fig.29.28 it was associated with renal failure.

Figure 29.28 Terry nails. Proximal pallor with distal brownish color, in a patient with chronic renal failure.

Half and half nails

The proximal half of the nail is white, while the distal half is red or pink in half and half nails, a marker of renal disease (Fig. 29.29).

Figure 29.29 Half and half nails. This may be a more prominent version of Terry nails (this patient also had renal failure).

Muercke lines

Transverse, arciform, white lines that are related to changes in the nail bed (and thus do not grow out with the nail) are characteristic. Edema of the underlying connective tissue seems to be the cause. They are most commonly associated with hypoalbuminemia (e.g. nephrotic syndrome) but may occur after trauma. These changes reverse when the edema resolves or the albumin is restored to normal. (Fig.29.30).

Figure 29.30 Muercke lines.

Yellow nail syndrome

In yellow nail syndrome (YNS), the nails become thickened, yellow, and grow very slowly (Fig.29.31). This condition is associated with pulmonary disorders (e.g. pleural effusion, chronic bronchitis, and bronchiectasis) and dysplasia of the lymphatics. One study suggested that the underlying cause of YNS is not primarily a lymphatic abnormality, and that the lymphatic impairment appears secondary and is predominantly functional rather than structural in nature (Fig. 29.32).

No treatment is uniformly effective. Some patients benefit from permanent avulsion, because the nail can become very thickened and painful. Benefit has been claimed from vitamin E preparations (e.g. topical vitamin E in dimethylsulfoxide) or from oral zinc sulfate (300mg/day), and antifungal agents sometimes appear to be effective, although no relevant infection can be demonstrated.

Figure 29.31 Yellow nail syndrome. All nails are thickened, yellow, and growing very slowly.

Figure 29.32 Yellow nail syndrome. The patient also had chronic lymphedema of the face, and the nails were dark, with longitudinal and transverse over-curvature.

Nail–patella syndrome

The lunula is triangular and the patellae are absent or hypoplastic in this syndrome with autosomal dominant inheritance. Hyperpigmentation of the pupillary margin of the iris (Lester iris) may also be seen, as well as glomerulonephritis with renal failure (Fig.29.33). The underlying gene, LMX1B on chromosome 9q34.1, is a transcription factor involved in the normal dorsoventral patterning of the limb and in normal development of the glomerular basement membrane in the kidney.

Figure 29.33 Nail–patella syndrome. (a) The nails are dystrophic, and (b) the radiograph of the knees shows absence of the left patella and a hypoplastic right patella.

White/Cox: Diseases of the Skin, 2ed.(c) 2006, Elsevier Inc. All rights reserved.