Nail discoloration, in which the nails appear white, yellow, or green, can result from different infections and conditions of the skin. In about 50% of cases, discolored nails are a result of infections with common fungi that can be found in the air, dust, and soil. There are many species of fungi that can affect nails. By far the most common, however, is called Trichophyton rubrum. This type of fungus has a tendency to infect the skin and is therefore known as a dermatophyte. Pseudomonas is a type of bacteria that infects the nail bed and results in a greenish color to the nails. Red or black (that may sometimes appear bruised) nails may result from a hematoma (a collection of blood) under the nail as a result of trauma (including ingrown toenails).
Chronic medical conditions also can affect the appearance of the nails. Specific color changes in the nails can be suggestive of diabetes or of liver, kidney, heart, or lung conditions. This is why doctors pay specific attention to nails during a routine physical examination.
Other, rare causes of discolored nails include the "yellow nail syndrome," an inherited condition that results in slow-growing, yellowing, discolored nails and is associated with lymphedema (swelling of tissues due to the accumulation of fluid) and lung diseases. Nails may also appear lightened to a whitish-yellow color if there has been separation of the nail from the nail bed, termed onycholysis.
The skin, mucous membranes, and nails may appear blue when there is inadequate oxygenation of blood (cyanosis), but this is not true discoloration of the nail itself.
REFERENCE:
Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.
Pictures, Images, Illustrations & Quizzes
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Nail Color and Texture: What Nails Say About Your Health
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Picture of Discoloration of Nail Plates
Many chemicals can discolor nail plates. Solutions of potassium permanganate and silver nitrate stain nail plates brown-purple...
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Picture of Fungal Nail Infection
Nails that are infected with a fungus may become discolored (yellowish-brown or opaque), thick and brittle, and may separate from...
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Picture of Onychomycosis (Fungal Nail Infection)
The most common fungus infection of the nails is onychomycosis. See a picture of Onychomycosis (Fungal Nail Infection) and learn...
Causes of Nail Discoloration
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Atopic Dermatitis
Eczema is a general term for many types dermatitis (skin inflammation). Atopic dermatitis is the most common of the many types of...
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Diabetes (Type 1 and Type 2)
Diabetes is a chronic condition characterized by high levels of sugar (glucose) in the blood. The two types of diabetes are...
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Fungal Nails
Fungal nails (onychomycosis) may be caused by many species of fungi, but the most common is Trichophyton rubrum. Distal subungal...
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Heart Disease
Heart disease (coronary artery disease) occurs when plaque builds up in the coronary arteries, the vessels that supply blood to...
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Hypertensive Kidney Disease
High blood pressure can damage the kidneys and is one of the leading causes of kidney failure (end-stage renal kidney disease)....
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Ingrown Toenail (Onychocryptosis)
Ingrown toenails are caused by the growth of the toenail into the surrounding nail fold. Symptoms and signs include toe pain,...
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Jaundice (Hyperbilirubinemia) in Adults
Jaundice (hyperbilirubinemia) in adults may be caused by a variety of medical diseases or conditions. Some cases of jaundice can...
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Lichen Planus
Lichen planus is a common skin disease that features small, itchy pink or purple spots on the arms or legs. the abnormal areas on...
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Liver Disease
Liver disease can be cause by a variety of things including infection (hepatitis), diseases such as: gallstones, high...
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Lymphedema
Lymphedema is a condition in which one or more extremities become swollen as the result of an impaired flow of the lymphatic...
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Psoriasis
Psoriasis is a long-term skin condition that may cause large plaques of red, raised skin, flakes of dry skin, and skin scales....
Other Causes of Nail Discoloration
- Bacterial Infection
- Candidiasis
- Chronic Lung Diseases
- Drug Hypersensitivity (for Example, Tetracycline)
- Malnutrition
- Senile Ischemia (Onychogryphosis)
- Onycholysis
- Staining From Nail Varnish or Cosmetic Products
- Trauma
- Yellow Nail Syndrome
Examples of Medications for Nail Discoloration
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