What It Is

example of discoloration in toenailsWhen something is wrong, one visible clue is nail discolouration. Healthy nails have a pinkish hue and are evenly coloured. Abnormal colouring varies depending on the cause, which may be a problem affecting the nails or a condition somewhere else in the body.

Signs & Symptoms

Yellow: Nails can become yellowed due to lymphedema (build-up of lymphatic fluid in tissues), lung disease or psoriasis.

Green: What is known as “green nail syndrome” is often caused by a type of fungal infection called Pseudomonas.

Brown: Nails may become stained brown from nicotine use, nail polish or even chemotherapy.

Purple: Bruising due to injury can turn part of a nail purple. Red or purple streaks can also result from a splinter hemorrhage (little bit of bleeding that occurs under the nail).

Blue: Nails can turn blue as a result of taking minocycline (antibiotic) and from several other oral medications.

Black: Usually from a pseudomonas infection, black nails can also be due to severe bruising. Some patients with darker skin tones may also experience uniform darkening or dark lines within nail with age. However, a subungual melanoma (see “Subungual melanoma” for information) must always be considered with black discoloration of nails.

White: White nails can be hereditary or a sign of low albumin (protein deficiency). White streaks may develop from trauma to the nail. Nails can also fade and turn white from vitiligo, which is a skin condition caused by a loss of pigmentation.