Discoloured nails

The most common causes of a yellow nail are fungal nail infections or nail psoriasis .

Yellow nails can also be caused by any of the following:

  • frequent application of nail varnish
  • lymphoedema a long-term condition that causes swelling of the skin
  • permanent damage to your airways caused by bronchiectasis a long-term lung condition
  • sinusitis inflammation of the lining of the sinuses
  • inflammation of the thyroid gland, found in the neck
  • tuberculosis (TB) abacterial infection affecting the lungs
  • jaundice (yellowing of the skin) caused by liver disease
  • some medications, such as mepacrine or carotene
  • chronic paronychia infection of the nail fold

Green-black nails can be caused by overgrowth of bacteria called pseudomonas, particularly under loose nails. It can be treated by applying antibiotic eye drops underneath the nails or soaking the affected nails in an antiseptic solution or vinegar.

Grey nails can be caused by medications such as antimalarials or minocycline.

Brown nails can sometimes be caused by thyroid disease, pregnancy, malnutrition and frequent use of nail varnish.

Red or yellow drop under the nail

If the discolouration looks like a drop of oil under the nail or is the colour of salmon, you may have psoriasis of the nails.

Half white, half brown nails

Fingernails that are half white and half brown (brown near the tips) can be a sign of kidney failure , where the kidneys stop working properly.

The link isn't fully understood, but one theory is that kidney failure causes chemical changes in the blood that encourage melanin (a skin pigment) to be released into the nail bed.It's also possible that kidney failure causes an increase in the number of tiny blood vessels in the nail bed.

It's estimated up to 40% of people with kidney failure have "half-and-half" fingernails. They also sometimes occur in people with AIDS and those who've had chemotherapy.

Content supplied by the NHS Website

Medically Reviewed by a doctor on 21 Dec 2018