A fungus is an organism that lives in warm moist areas. Fungus of the toenails is a common problem that can affect people of all ages, although it most commonly affects individuals who are older.
Toenail fungus often begins as an infection in the skin called tinea pedis (also known as athlete’s foot). The fungus often starts under the nail fold at the end of the nail. Over time it grows underneath the nail and causes changes to its appearance, such as a yellow or brownish discoloration. It can also cause thickening and deformity of the toenail.
Many people have difficulty with their toenails and need assistance in caring for them. A foot and ankle surgeon can diagnose the cause of toenail problems and recommend treatments.
A black, purple, or brownish discoloration under or involving a toenail is frequently due to trauma to the toe nail, such as when something is dropped on the toe. The color results from a blood clot or bleeding under the nail, and may involve the entire nail or just a small portion of it. This can be very painful when the entire nail is involved, and may need medical attention to relieve the pressure caused by bleeding under the toenail.
Although it is very rare, a more serious cause of black toenails is malignant melanoma. Since early diagnosis and treatment of melanoma improves the chances for a good outcome, it is important that all black toenails be evaluated by a qualified foot and ankle surgeon to rule out this cause.
Other rare causes of black toenails include fungal infections, chronic ingrown nails, or health problems affecting the rest of the body.
Toenails will often become thick as an individual grows older. Thickening may also occur as a result of trauma to the toenail, such as when it repeatedly hits the end of a shoe that is too short. Sometimes when something is dropped on the toenail, the nail will fall off. When a new toenail grows back it will often be thicker than it was previously.
Thick toenails can also be seen in individuals with nail fungus (onychomycosis), psoriasis, and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment.
White toenails can develop for several reasons.
- Trauma, such as when an object is dropped on a toenail, often causes bleeding under the nail because of blood vessels being broken. This would cause a black toenail. If the trauma does not cause broken blood vessels, a white spot may appear under the nail. The spot will slowly grow out with the normal growth of the toenail.
- Sometimes white lines appear within the toenail. These may be caused by recurring trauma, such as when a runner wears shoes that are too small and the toe hits the end of the shoe.
- White lines may also occur due to a medical illness or trauma that has occurred elsewhere in the body, causing protein to be deposited within the nail bed.
- A fungal infection that affects the outermost layer of the toenail may cause a bright white discoloration of the toenail.
- A white area close to the nail fold (the lunula) varies in size from one person to another. This is a normal aspect of the nail.
- It is recommended that you see a foot and ankle surgeon for the diagnosis and possible treatment of white toenails.
The most common cause of yellow discoloration in the toenails is a fungal infection. The fungus often develops underneath the nail, resulting in it becoming thick, raised, and yellow in color.
Other potential causes for yellow discoloration of the nail include diabetes mellitus and lymphedema (chronic leg swelling). Yellow staining of the nails can also occur in individuals who use nail polish. A stained nail may take several months to grow out.