Dr Mel Wynne-Jones reveals what different colour changes may mean and the four tests you may need
We quickly notice sudden colour changes in ourselves or others, but it can take longer when they’re subtle, develop slowly, or are hidden by clothes. There’s often a simple reason (such as fabric dye in clothing), but skin and other changes can sometimes be a sign of illness.
Our skin colour depends on brown pigment (melanin) and blood vessels beneath the surface – we can look paler, even if we’re naturally dark-skinned. Sudden pallor can be a sign of physical/emotional shock (for example, severe bleeding) as our bodies divert blood to our brains and other essential organs; we’ll probably feel clammy and faint.
Fingers and toes may go white or blue even when it’s not very cold because we have Raynaud’s disease, a disorder of tiny surface blood vessels.
Slowly developing pallor can indicate anaemia, caused by iron/vitamin deficiency, heavy periods, internal bleeding or bone marrow problems; nails and inner lower eyelids will look pale, too.
White skin patches, where the colour has disappeared completely, can be caused by fungal infections or vitiligo, an immune disorder that may also affect hair, or be linked to diabetes or thyroid disease.
Flushing occurs when skin blood vessels dilate, usually to cool us down, for example because of hot environments, the menopause, an overactive thyroid, alcohol, medication, or some cancers.
Cushing’s disease (overproduction of steroids by the adrenal glands) produces a red ‘moon’ face (prescribed steroids can do this, too). Polycythaemia rubra vera (too many red blood cells – a bone marrow disorder) and carbon monoxide poisoning also produce facial redness; liver disease turns the palms red.
Localised redness occurs in inflammation, such as skin infection (cellulitis), eczema, psoriasis or rosacea (‘adult acne’), often with itching, pain, swelling and/or scaling.
A sore red tongue can be due to vitamin deficiencies; red (or white) patches in the mouth or genitals are occasionally cancerous. Red stools or urine may mean blood and, like unexpected vaginal bleeding, can have serious causes so should be promptly reported to your GP.
Sunlight turns skin browner, but a new mole, changes in an existing mole, or a black patch under a fingernail should always be checked for cancer.
Excessive pigmentation, for example, in skin creases, can be due to Addison’s disease (underactive adrenal glands); ‘bronzing’ may be due to haemochromatosis, a genetic condition that deposits iron in the skin and liver.
A black hairy tongue develops when bacteria or yeasts build up, and can be cured by tongue-brushing and good mouth hygiene. Fungal nail infections can cause brown/black thickening and crumbling, while poor circulation can lead to blackened skin (gangrene).
Low blood oxygen levels (for example, heart/lung disease) turn fingernails, lips and tongues blue. Bruises (bleeding into the skin) start off blue/purple before turning green and yellow.
Sudden unexplained bruises may indicate a blood disorder, and in someone who is unwell, could signal the life-threatening infection, meningitis/septicaemia, if they don’t disappear when pressed with a glass.
Yellow/orange and green
Yellow jaundice can colour the skin, nails and whites of the eyes; it’s due to a build-up of waste products when the liver, gall bladder and/or pancreas aren’t working properly.
You may also notice pale stools and dark urine. Kidney failure can produce orange-ish skin, while green nails are usually infected with Pseudomonas bacteria.
4 tests you may need
1. Blood tests for anaemia, diabetes, liver/kidney/thyroid function, oxygen levels and immune disorders.
2. Urine tests for blood, diabetes and signs of kidney damage.
3. X-rays, or scans of relevant internal organs.
4. Biopsy (small tissue sample) or removal of abnormal skin/nails.