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About 50% of nail deformities result from fungal infection. The remainder results from various causes, including trauma, psoriasis, lichen planus, and occasionally malignancy. Diagnosis may be obvious on examination, but sometimes fungal scrapings and culture may be performed. Once any underlying conditions are addressed, manicurists may be able to hide nail deformities with appropriate trimming and polishes.
Congenital deformities:
In some congenital ectodermal dysplasias, patients have no nails (anonychia). In pachyonychia congenita, the nail beds are thickened, discolored, and hypercurved with a pincer nail deformity. Nail-patella syndrome (see Bone and Connective Tissue Disorders in Children: Nail-Patella Syndrome) causes triangular lunulae and partially absent thumb nails. Darier's disease is associated with red and white streaks and distal V-nicking.
Deformities
associated with systemic problems:
In the Plummer-Vinson syndrome, 50% of patients have koilonychia—concave, spoon-shaped nails. The yellow nail syndrome, characterized by hard, hypercurved, transversely thickened, yellow nails with loss of the cuticle, is seen in patients with lymphedema of limbs, pleural effusion, and ascites. Half-and-half nails occur with renal failure; the proximal half of the nail is white, and the distal half is pink or pigmented. White nails occur with cirrhosis, although the distal third may remain pinker.
Deformities
associated with dermatologic conditions:
In psoriasis, nails may demonstrate a number of changes including irregular pits, oil spots, onycholysis, and thickening and crumbling of the nail plate. Lichen planus of the nail matrix causes scarring with early nail ridging and splitting, then later leading to pterygium formation. Pterygium of the nail is characterized by scarring from the proximal nail outward in a V formation, which leads ultimately to loss of the nail. Alopecia areata is associated with regular pits that form a pattern.
Discoloration:
Drugs, especially cytostatic and antimalarial drugs, can discolor nails. The drugs most commonly involved are bleomycin and cyclophosphamide and less commonly, actinomycin, doxorubicin , busulfan , 5- fluorouracil , hydroxyurea , and melphalan . Quinacrine can cause nails to appear greenish yellow or white under ultraviolet light. In argyria, the nails may be diffusely blue gray. With arsenic intoxication, the nails may turn diffusely brown. Tetracyclines, ketoconazole , phenothiazines, sulfonamides, and phenindione can all cause brownish or blue discoloration. Gold therapy can turn nails light or dark brown.
White transverse lines of the nails (Mees' lines) may occur with chemotherapy, acute arsenic intoxication, malignant tumors, MI, thallium and antimony intoxication, fluorosis, and even during etretinate therapy. They also develop with trauma to the finger, although traumatic white lines usually do not span the entire nail. The fungus Trichophyton mentagrophytes causes a chalky white discoloration of the nail plate.
Melanonychia
striata:
These are hyperpigmented longitudinal bands extending from the proximal nail fold and cuticle to the free distal end of the nail plate. In dark-skinned people, these may be a normal physiologic variant requiring no treatment. Melanonychia striata can also occur in benign melanocytic nevi and malignant melanoma. Hutchinson's sign—melanin leaching through the lunula, cuticle, and proximal nail fold—may signal a melanoma in the nail matrix. Rapid biopsy and treatment are essential.
Onychogryphosis:
Onychogryphosis is a nail dystrophy in which the nail, most often on the big toe, becomes thickened and curved. It may be caused by ill-fitting shoes. It is common in the elderly. Treatment consists of trimming the deformed nails.
Onycholysis:
Onycholysis is separation of the nail plate from the nail bed or complete nail plate loss. It can occur as a phototoxic reaction in patients treated with tetracyclines (photo-onycholysis), doxorubicin , 5- fluorouracil , β-blockers (particularly practolol and captopril ), cloxacillin and cephaloridine (rarely), sulfamethoxazole- trimethoprim , diflunisal , etretinate, indomethacin , isoniazid , and isotretinoin . Partial onycholysis may also occur from infection with Candida albicans, from trauma, and in association with psoriasis or thyrotoxicosis.
Onychotillomania:
In this disorder, patients pick at and self-mutilate their nails, which can lead to washboard deformity or habit-tic nails. Subungual hemorrhages can also be seen in onychotillomania. It most commonly presents in patients who habitually push back the cuticle on one finger, causing dystrophy of the nail plate as it grows.
Trachyonychia:
Trachyonychia—rough, opaque nails— may occur with alopecia areata, lichen planus, atropic dermatitis, and psoriasis. It is most frequent in children.
Trauma:
Damage to the nail bed, particularly crush injury, sometimes results in permanent nail deformity. Risk is reduced by primary repair at the time of injury.
Tumors:
Benign and malignant tumors can affect the nail unit, causing deformity. These include benign myxoid cysts, pyogenic granulomas, glomus tumors, Bowen's disease, squamous cell carcinoma, and malignant melanoma. When malignancy is suspected, expeditious biopsy followed by referral to a surgeon is strongly advised.
Last full review/revision November 2005
Content last modified November 2005
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