Deformities, Dystrophies, and Discoloration of the Nails - Skin Disorders - Merck Manuals Consumer Version (2024)

Some babies are born without nails (anonychia). In nail-patella syndrome Nail-Patella Syndrome Nail-patella syndrome is a rare hereditary disorder that results in abnormalities of the kidneys, bones, joints, toenails, and fingernails. Nail-patella syndrome is caused by a mutation of a... read more , thumbnails are missing or are small with pitting and ridges. Darier disease causes red and white streaks on the nails and V-shaped notches to form on the tips of the nails. In pachyonychia congenita, nail beds (the parts of the nail unit that attach the nail to the finger) are thickened and discolored and are curved from side to side, forming a pincer nail deformity Pincer nail deformity The terms deformities and dystrophies are often used interchangeably, sometimes even by doctors. However, their meanings are slightly different. Deformities: Changes in nail shape... read more .

• Iron deficiency Iron Deficiency Iron deficiency is a common cause of anemia, a condition in which the number of red blood cells is low. Iron deficiency usually results from loss of blood in adults (including bleeding from... read more may cause spoon-shaped nails (koilonychia). This deformity is particularly characteristic of Plummer-Vinson syndrome Esophageal Webs Esophageal webs are thin membranes that grow across the inside of the upper part of the esophagus and may cause difficulty swallowing (dysphagia). (See also Overview of Esophageal Obstructions... read more .

• Kidney failure Overview of Kidney Failure Kidney failure is the inability of the kidneys to adequately filter metabolic waste products from the blood. Kidney failure has many possible causes. Some lead to a rapid decline in kidney function... read more may cause the bottom half of the nails to turn white and the top half of the nails to turn pink or appear pigmented (half-and-half nails or Lindsay nails). This dystrophy can also occur in healthy people.

• Cirrhosis Cirrhosis of the Liver Cirrhosis is the widespread distortion of the liver's internal structure that occurs when a large amount of normal liver tissue is permanently replaced with nonfunctioning scar tissue. The scar... read more may cause the nails to turn white, although the very top part of the nails may remain pinker. Intensely white nails, also called Terry nails, can be present not only in people with cirrhosis but also in those with chronic heart failure or diabetes. Low blood levels of the protein albumin (which may occur in people with cirrhosis) can cause horizontal white lines to form on the nails. Terry nails may sometimes occur as part of normal aging.

• Some lung diseases, often accompanied by lymphedema Lymphedema Lymphedema is the accumulation of lymph in tissues, resulting in swelling. When lymphatic vessels are injured or obstructed, lymph fluid cannot drain and accumulates in tissues, causing swelling... read more (an accumulation of lymphatic fluid in tissues), may cause yellow nail syndrome, in which nails become thick, overcurved, and yellow or yellow-green in color.

• Beau lines are horizontal grooves in the nail that occur when there is temporary slowing of growth of the nail. Sometimes the grooves can go all the way through the nail, leading to complete loss of the nail. They can occur after an infection, injury, systemic illness, or chemotherapy.

• White horizontal lines across part of the nail (leukonychia) may appear after an injury. However, lines that run horizontally all of the way across the nail (Mees lines) may be associated with more serious health problems, including cancer or heart failure, chemotherapy, or exposure to certain toxins, such as arsenic, thallium, or other heavy metals. The nails can grow out normally if exposure to these toxins or chemotherapy is stopped.

• In psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more , nails may have irregular pits (tiny depressions in the surface of the nail), oil spots (yellow-brown spots under the nail), separation of the nail plate from its bed (onycholysis), and thickening and crumbling of the nail plate.

• Lichen planus Lichen Planus Lichen planus, a recurring itchy disease, starts as a rash of small, separate, red or purple bumps that then combine and become rough, scaly patches. The cause is unknown but may be a reaction... read more of the nail matrix causes scarring with early nail ridging and splitting, later leading to scarring and pterygium formation. Pterygium of the nail, which is caused by lichen planus, is scarring from the base of the nail outward in a V formation, which leads to loss of the nail.

• People with alopecia areata Alopecia Areata Alopecia areata is sudden loss of patches of hair when there is no obvious cause such as a skin or general internal disorder. (See also Overview of Hair Growth and Hair Loss [Alopecia].) Alopecia... read more , a disorder in which round, irregular patches of hair are suddenly lost, may have nail pits that form a geometric pattern.

• People who have alopecia areata, lichen planus, atopic dermatitis Atopic Dermatitis (Eczema) Atopic dermatitis (commonly referred to as eczema) is chronic, itchy inflammation of the upper layers of the skin that often develops in people who have hay fever or asthma and in people who... read more , or psoriasis may develop trachyonychia (rough, opaque nails that have ridges and a sandpaper-like appearance). Trachyonychia most frequently occurs in children.

• Chemotherapy drugs may cause a darkening (hyperpigmentation) of the nail plate. Horizontal pigmented or white bands may also be seen in people treated with certain chemotherapy drugs.

• Chloroquine, a drug used in the treatment of parasitic infections and certain types of autoimmune diseases, can cause the nail bed to turn blue-black.

• Silver, which can be absorbed after occupational exposure or through taking dietary supplements containing colloidal silver protein, can cause the nails to turn a dark blue-gray.

• Drugs that contain gold, which is rarely used in the treatment of rheumatoid arthritis, can turn nails light or dark brown.

• Tetracycline antibiotics, ketoconazole, sulfonamide antibiotics, phenindione, and phenothiazines can cause blue or brown discoloration.

• Zidovudine (ZDV), a drug used to treat human immunodeficiency virus (HIV) infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and is treated with antiretroviral medications. If untreated, it can cause... read more , may cause brown-black longitudinal streaks. However, these streaks can also be present in people who have AIDS but are not receiving ZDV.

• Arsenic poisoning can cause horizontal white lines to form on the nails or cause the nails to turn brown.

Melanonychia striata are gray, brown, or black lines in the nail plate caused by the normal, brown skin pigment, melanin. The lines extend from the base of the nail to its tip. In dark-skinned people, these lines may be normal and require no treatment. Other noncancerous causes of melanonychia striata include moles Moles Moles are small, usually dark, skin growths that develop from pigment-producing cells in the skin (melanocytes). Most people have some moles, but the tendency to develop atypical moles is sometimes... read more , HIV infection Human Immunodeficiency Virus (HIV) Infection Human immunodeficiency virus (HIV) infection is a viral infection that progressively destroys certain white blood cells and is treated with antiretroviral medications. If untreated, it can cause... read more , hyperthyroidism Hyperthyroidism Hyperthyroidism is overactivity of the thyroid gland that leads to high levels of thyroid hormones and speeding up of vital body functions. Graves disease is the most common cause of hyperthyroidism... read more , use of certain drugs, pregnancy, nail injuries Fingernail and Toenail Injury Fingernails and toenails can be damaged by injuries. Even a minor injury to the finger or toe may cause changes in the nail. Severe damage to the nail bed (the soft tissue underneath the nail... read more , Addison disease Adrenal Insufficiency In adrenal insufficiency, the adrenal glands do not produce enough adrenal hormones. Adrenal insufficiency may be caused by a disorder of the adrenal glands, a disorder of the pituitary gland... read more , and Cushing syndrome Cushing Syndrome In Cushing syndrome, the level of corticosteroids is excessive, usually due to taking corticosteroid drugs or overproduction by the adrenal glands. Cushing syndrome usually results from taking... read more .

However, similar dark lines or discoloration in or around a nail can be an early sign of cancer, particularly melanoma Melanoma Melanoma is a skin cancer that begins in the pigment-producing cells of the skin (melanocytes). Melanomas can begin on normal skin or in existing moles. They may be irregular, flat or raised... read more , which can develop from the pigment cells of the nail-making tissue (nail matrix). Doctors usually do a biopsy of the nail matrix if they are concerned a discoloration might be cancerous.

• An injury (such as in prolonged hiking or skiing with poorly fitted footwear)

• Overzealous nail cleaning

• Psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more and thyrotoxicosis Hyperthyroidism Hyperthyroidism is overactivity of the thyroid gland that leads to high levels of thyroid hormones and speeding up of vital body functions. Graves disease is the most common cause of hyperthyroidism... read more

• Frequent exposure to water, citrus fruits, and certain chemicals (such as those in cleaning agents)

• Treatment with doxorubicin, captopril, practolol, 5-fluorouracil, and retinoids

• Onychomycosis Onychomycosis Onychomycosis is a fungal infection of the nails. (See also Overview of Nail Disorders.) About 10% of people have onychomycosis, which most often affects the toenails rather than the fingernails... read more

In pincer nail deformity, the nail is overcurved horizontally (side-to-side). It is most often caused by a fungal infection (onychomycosis Onychomycosis Onychomycosis is a fungal infection of the nails. (See also Overview of Nail Disorders.) About 10% of people have onychomycosis, which most often affects the toenails rather than the fingernails... read more ), psoriasis Psoriasis Psoriasis is a chronic, recurring disease that causes one or more raised, red patches that have silvery scales and a distinct border between the patch and normal skin. A problem with the immune... read more , tumors of the nail Tumors of the Nails Noncancerous (benign) and cancerous (malignant) tumors can affect the nail unit, causing a changes in nail texture and/or color ( dystrophy). Many of these are tumors that originate in tissues... read more , and poorly fitting shoes. The deformity can also occur in people who have lupus Systemic Lupus Erythematosus (SLE) Systemic lupus erythematosus is a chronic autoimmune inflammatory connective tissue disorder that can involve joints, kidneys, skin, mucous membranes, and blood vessel walls. Problems in the... read more , Kawasaki disease Kawasaki Disease Kawasaki disease causes inflammation of blood vessels throughout the body. The cause of Kawasaki disease is unknown but may be associated with an infection. Children typically have fever, rash... read more , end-stage renal disease (severe chronic kidney disease Chronic Kidney Disease Chronic kidney disease is a slowly progressive (months to years) decline in the kidneys’ ability to filter metabolic waste products from the blood. Major causes are diabetes and high blood pressure... read more ), and some genetic syndromes (for example, pachyonychia congenita). Sometimes it develops in older people and in those with arthritis in their fingers. People often have pain where the nail plate curves into the tips of the fingers.