FINGERNAILS

[Guest guest]

Definition: Nail abnormalities are problems with the color, shape, texture, or thickness of the fingernails or toenails. Alternative Names: Beau's lines; Fingernail abnormalities; Spoon nails; Onycholysis; Leukonychia; Koilonychia; Brittle nails Considerations: Just like the skin, the fingernails tell a lot about your health. Pitting is the presence of small depressions on the nail surface. Pitting nails are often accompanied with crumbling of the nail. The nail can becomes loose and

sometimes fall off. Ridges are tiny, raised lines (linear elevations) that develop across or up and down the nail. Beau's lines are linear depressions that occur sideways (across) on the fingernail. These lines can occur after illness, injury to the nail, and when you are malnourished. Leukonychia is white streaks or spots on the nails. Koilonychia is an abnormal shape of the fingernail where the nail has raised ridges and is thin and concave. This disorder is associated with iron deficiency anemia. Brittle nails are often a normal result of aging, but may also be due to certain diseases and conditions. Common Causes: Injury: Crushing the base of the nail or the nail bed may cause a permanent

deformity. Chronic picking or rubbing of the skin behind the nail can cause a washboard nail. Long-term use exposure to moisture or nail polish can cause nails to peel and become brittle. Infection: Fungus or yeast cause changes in the color, texture, and shape of the nails. Bacterial infection may cause a change in nail color or painful areas of infection under the nail or in the surrounding skin. Severe infections may cause nail loss. Viral warts may cause a change in the shape of the nail or ingrown skin under the nail. Certain infections (especially of the heart valve) may cause splinter hemorrhages (red streaks in the nail bed). Diseases: Disorders that affect the amount of oxygen in the blood (such as abnormal heart anatomy and

lung diseases including cancer or infection) may cause clubbing. Kidney disease can causes a build-up of nitrogen waste products in the blood, which can damage nails. Liver disease can damage nails. Thyroid diseases including hyperthyroidism or hypothyroidism may cause brittle nails or splitting of the nail bed from the nail plate (onycholysis). Severe illness or surgery may cause horizontal depressions in the nails (Beau's lines). Psoriasis may cause pitting, splitting of nail plate from nail bed (onycholysis), and chronic destruction of the nail

plate (nail dystrophy) Other conditions that can affect the appearance of nails include systemic amyloidosis, malnutrition, vitamin deficiency, and lichen planus. Poisons: Arsenic poisoning may cause white lines and horizontal ridges. Silver intake can cause a blue nail. The primary function of the nail is protection. Nail concerns are common, but the exact prevalence of nail disease is unknown. Nail disease occurs with certain skin diseases (psoriasis, eczema), often follows external trauma, may be an adverse effect of medication, and may occur with

certain illnesses. The most common cause of nail disease is infection, usually fungal (onychomycosis) and less often bacterial. In many respects, the nails may indicate or reflect medical illness. NAIL ABNORMALITIES AND SYSTEMIC DISEASEDRUG-INDUCED NAIL ABNORMALITIES INFECTIONSOF THE NAIL TUMORS OF THE NAIL Benign Tumors Malignant Tumors GENETIC NAIL ABNORMALITIES RecommendedReferences BASIC NAIL ANATOMY The nail plate is a hard keratinized structure derived from keratinocytes within the nail matrix, which begins proximal to the nail plate and extends to the lunula, the white half-moon shaped portion often seen through the nail plate. The proximal and distal nail matrices generate the dorsal and ventral nail plate, respectively. The nail bed beneath the nail plate extends from the lunula to the hyponychium, and the hyponychium lies under the free edge of the nail plate. The proximal and lateral nail folds comprise the paronychium. NAIL ABNORMALITIESAND SYSTEMIC

DISEASE BEAU'S LINES Beau's lines (Figure 1) are transverse depressions in the nail plate that often follow local trauma. They may reflect poor nutritional status, febrile illness, or a reaction to medication. Occasionally, they occur with eczema, usually atopic or chronic hand eczema. Beau's lines are a temporary cessation in nail growth and tend to appear about one month after the inciting event. Beau's lines tend to resolve spontaneously, by moving distally. ONYCHOLYSIS Onycholysis (Figure 2) is the distal separation of the nail plate from the underlying nail bed. Onycholysis often occurs with thyroid disease, either hyperthyroidism or hypothyroidism, and commonly occurs with psoriasis and eczema. It may occur with porphyria cutanea tarda, lichen planus, eczema, and with some of the autoimmune blistering diseases; it may also indicate an adverse reaction to medication, for example, tetracycline. Onycholysis may be persistent. ONYCHOMADESIS Onychomadesis is the proximal separation of the nail plate from the nail bed, which typically results in shedding of the nail. Trauma is the usual cause. Less common causes include poor nutritional status, febrile illness, or drug sensitivity. The inciting event causes complete cessation of nail matrix activity. Loss of the nail may or may not be permanent. ONYCHORRHEXIS Onychorrhexis (Figure 3) is the presence of longitudinal striations or ridging of the nails. These striations may simply reflect advanced age, but they do occur in some patients with rheumatoid arthritis, peripheral vascular disease, lichen planus, or Darier's disease. Longitudinal red/white striations invariably occur with Darier's disease, and V-shaped notching or nicking of the free edges of the nails are also common. Onychorrhexis is usually persistent. KOILONYCHIA The spoon-shaped, concave nails of koilonychia (Figure 4) commonly occur with iron-deficiency anemia and Plummer-Vinson syndrome, as a result of thinning and softening of the nail plate. Spoon-shaped nails are a normal, physiologic occurrence in children. Koilonychia tends to resolve, either with treatment or with aging (children). CLUBBING Clubbing (Figure 5) is an increase in the transverse and longitudinal nail curvature and fibrovascular

hyperplasia of the soft tissue proximal to the cuticle. With clubbing, the angle (Lovibond's angle) formed between the dorsal distal phalanx and the nail plate is increased. Clubbing occurs frequently with cardiopulmonary disease, for example aortic aneurysm and bronchogenic carcinoma. The change is usually permanent. SPLINTER HEMORRHAGES Splinter hemorrhages often follow trauma to the nail, but classically occur in patients with bacterial endocarditis, less so in patients with rheumatoid arthritis, trichinosis, and renal disease, esp. those on dialysis. Splinter hemorrhages

represent extravasation of blood from the vessels of the nail bed. They may resolve, recur, or persist. LEUKONYCHIA Leukonychia (Figure 6) is a white discoloration of the nail secondary to color change in the nail bed. Leukonychia includes Terry's nails, half-and-half nails, and Muehrcke's lines. Terry's nails exhibit almost complete discoloration except for the distal edge; they occur most commonly with cirrhosis and congestive heart failure. The discoloration of half-and-half nails affects the proximal half of the nail;

they occur with chronic renal failure. Muehrcke's lines (Figure 7) are narrow, white transverse lines (usually two); they occur with hypoalbuminemia. Mee's lines (Figure 8) resemble Muehrcke's lines, but the lines are thicker and may be single or multiple. Mee's lines occur with arsenic exposure. YELLOW NAIL SYNDROME Yellow nail syndrome (Figure 9) is a permanent cessation of nail growth resulting in hard, thickened, curved, yellow nails, occasionally with onycholysis. Yellow nails occur with lymphedema, chronic bronchitis, or bronchiectasis. Yellow nails tend to be persistent. PITTING Pitting, (Figure 10) or small punctate depressions in the nail plate, most commonly occurs with psoriasis, less so with

alopecia areata and eczema. The pits represent abnormal keratinization in the nail matrix. In most cases, the treatment of skin disease has little if any effect on the nail disease. TRACHYONYCHIA Trachyonychia (Figures 11 and 12), or twenty nail dystrophy, is a longitudinal ridging and roughness of the nails.

Though uncommon, it occurs with psoriasis, lichen planus, alopecia areata, and eczema. Treatment of skin disease usually has no effect on the ridging and roughness. OIL SPOTS Oil spots or "oil droplets"—orange-brown patches seen through the nail plate—are characteristic of psoriasis. Psoriatic nail disease is often associated with psoriatic arthropathy. PTERYGIUM Pterygium (Figure 13) is an adhesion of the proximal nail fold to the proximal nail bed following inflammation that destroys the nail matrix. Scar formation may occur, leading to partial loss of the nail plate. Pterygium occurs almost exclusively with lichen planus. PTERYGIUM INVERSUS UNGUIS Pterytium inversus unguis (Figure 14), or ventral pterygium, occurs with connective tissue disease, especially progressive systemic

scleroderma and systemic lupus erythematosus. Pterygium inversus is an adhesion of the distal nail bed to the ventral nail plate; soft tissue is attached firmly to the underneath side of the nail plate. There is no satisfactory treatment for pterygium. DRUG-INDUCED NAIL ABNORMALITIES Many drugs can produce nail disease. Some characteristic abnormalities include the following (Table 1). Table 1: Systemic Drugs Inducing Nail Changes Drug Nail Finding Antineoplasticdrugs Hyperpigmentation, leukonychia, splinter hemorrhages, Beau's lines, onycholysis, onychomadesis Arsenic Mee's

lines Azidothymidine Melanonychia Beta-blockers Thickening and pitting, Beau's lines, ischemic changes Chloroquine Blue-grey to yellow pigmentation Chlorpromazine Blue-purple pigmentation Indinavir Paronychia, pyogenic granuloma Minocycline Blue-grey pigmentation Psoralens/PUVA Photo-onycholysis Retinoids Brittleness, pyogenic granuloma-like growths Tetracycline Photo-onycholysis If the offending drug is discontinued, the abnormality typically disappears, except for pyogenic granuloma. INFECTIONS OF THE NAIL ONYCHOMYCOSIS Onychomycosis (Figure 15 and 16), or tinea unguium, is a fungal or yeast infection of the nail, usually caused by Tinea rubrum, T. mentagrophytes, or Candida albicans. Onychomycosis is the most common nail disorder. Predisposing factors for infection include heat, moisture, trauma, diabetes mellitus, and tinea pedis. Affected nails are dystrophic and hyperkeratotic (thickened), often with yellow-brown discoloration. Discomfort

may occur. Treatment is warranted for onychomycosis of the fingernails and whenever discomfort occurs. Treatment can be symptomtatic, frequently with the aid of a podiatrist for toenail onychomycosis. If warranted, systemic treatment involves the use of either terbinafine or itraconazole. Success with either agent is less than 50%, and recurrences are common. PARONYCHIA Acute paronychia (Figure 17) is an inflammation of the proximal and lateral nail folds characterized by erythema, edema, and pain. Purulent drainage with

compression behind the cuticle may also occur. Trauma is often the initial event with secondary infection with Staphylococcus aureus or Streptococcus pyogenes. Treatment usually requires compresses and an oral anti-staphylococcal antibiotic. Chronic paronychia is usually a non-infectious disease that follows irritant or allergic contact dermatitis of the proximal nail fold. The cuticle is invariably absent. Affected individuals often trim the cuticles aggressively and meticulously and/or do "wet work' with their hands. Secondary infection with Candida albicans is common. Treatment involves aeration, topical corticosteroids, and perhaps an oral antifungal agent, for example, terbinafine, for secondary infection. WARTS Warts (Figure 18), or verruca vulgaris, are an infection of the proximal and lateral nail folds caused by human papilloma virus (HPV), types 1, 2, and 4 are primarily responsible for periungual warts. Because of the location, these warts are particularly difficult to treat, especially if they extend subungually. Subungual warts may cause deformity or discoloration of the nail plate. Affected patients are often 'nail biters.' TUMORS OF THE NAIL BENIGN TUMORS MUCOUS CYST A mucous or myxoid cyst (Figure 19) is a soft nodule at the proximal nail fold, which may intermittently drain viscous fluid; less commonly, it may occur subungually. The cyst, a collection of degenerative collagen, may cause a longitudinal depression or groove in the nail plate from compression of the

nail matrix. Occasionally, it may connect to the underlying joint space and is often associated with osteoarthritis of the distal interphalangeal joints. Treatment is excision. SUBUNQUAL EXOSTOSIS Subunqual exostosis is essentially a hard, painful, subungual tumor, most commonly on the great toe. The exostosis typically occurs with trauma and often causes elevation of the distal nail plate. Exostosis is an outgrowth of normal bone. Treatment is symptomatic, for example, orthotics and analgesics, though surgery may be necessary for some patients. PERIUNGUAL FIBROMAS Periungual fibromas (Figure 20), or Köenen's tumors, are flesh-colored to pink papules that originate from the nail bed and cause a longitudinal depression in the nail plate. These fibromas may occur spontaneously, but are often associated with tuberous sclerosis. Treatment is often unnecessary; however, excision is curative. PYOGENIC GRANULOMA A pyogenic granuloma (Figure 21) is a benign vascular tumor that usually develops after trauma and occasionally with pregnancy and some medication (Table 1). Characterized by rapid growth and a blue-red color, the nodule/tumor bleeds easily with minimal trauma. Surgical excision is the treatment of choice. GLOMUS TUMOR The glomus tumor (Figure 22) is a benign vascular growth, arising from glomus cells of the nail bed. The tumor is usually a red-blue macule (patch) within the nail bed visible through the nail plate. Pain or pressure and sensitivity to changes in temperature are common. Treatment, via excision, is often necessary for symptomatic relief. MALIGNANT TUMORS LONGITUDINAL MELANONYCHIAAND MELANOMA Longitudinal melanonychia (Figure 23), brown-pigmented longitudinal streaks of the nail, may be a normal variant in darker-skin individuals (Figure 24), or they may actually be nevi. Less commonly, they may represent 's disease, acanthosis nigricans, Peutz-Jeghers syndrome, trauma, subungual hemorrhage, and fungal infection, or even an underyling melanoma, especially when they occur on the thumb (most common site for melanoma of the nail unit). Black discoloration of the proximal nail fold at the base of the pigmented streak (Hutchinson's sign) is an ominous sign for melanoma. Longitudinal melanonychia in

one nail without an obvious explanation warrants a biopsy of the nail matrix. Melanoma of the nail unit has a poor prognosis. SQUAMOUS CELL CARCINOMA Squamous cell carcinoma (SCC) is the most common malignancy of the nail unit (Figure 25). SCC is usually a verrucal (warty) plaque on the lateral nail fold of the finger, and may resemble a wart unresponsive to traditional therapy. SCC is associated with HPV-16 infection and less so with trauma and radiation. SCC of the nail unit grows slowly and metastasis is rare.

GENETIC NAIL ABNORMALITIES Many genetic disorders have distinctive nail abnormalities. Nail patella syndrome (Figure 26) exhibits triangular lunulae, in addition to renal disease and skeletal abnormalities. Pachyonychia congenita, an ectodermal dysplasia, exhibits marked subungual hyperkeratosis and increased transverse curvature of the nails (pincer nails, Figure 27). Other genetic disorders with nail findings include: hidrotic ectodermal dysplasia (thickening, longitudinal striations, absence of nails); dyskeratosis congenita (pterygium, absence of nails); epidermolysis bullosa (absence of nails), and Darier's disease (V-shaped nicking, red and white longitudinal striations, onychorrhexis, Figure 28). SUMMARY This chapter outlines the major causes of nail disease. An underlying systemic or skin

disease may be associated with nail dystrophy. In other cases, trauma, medications, or nail unit tumors may be responsible. Definitive treatment is often difficult; treatment for infections and tumors is usually straight-forward, though many nail disorders simply require observation and reassurance. Return to Medicine Index RECOMMENDED REFERENCES Drake LA, Dinehart SM, Farmer EM, et al. Guidelines of care for nail disorders. J Am Acad Dermatol. 1996;34:529-33. Piraccini BM, Tosti A. Treatment of common nail disorders. Derm Clinics. 2000;18:339-48. Rich P. Nail biopsy: indications and methods. Dermatol Surg. 2001;27:229-34. Rich P. Nail disorders: Diagnosis and treatment of infectious, inflammatory, and neoplastic nail conditions. Med Clin North Am. 1998;82:1171-83. M. Nail manifestations of some important genetic disorders in children. Dermatologic Therapy. 2002;15:111-20. Spencer JM. Malignant tumors of the nail unit. Dermatologic Therapy. 2002;15:126-30. GENTLE HUGS, CHRISTINA

~ 777