If your feet have become discoloured, this may be an indication of a serious underlying medical problem that needs immediate attention.
Blue-tinged feet may mean that you are suffering from cyanosis, according to the National Institutes of Health. The mucus membranes or skin can turn blue due to lack of oxygen in the blood. The blue tint can also appear on your nose, ears, lips, gums, around your eyes and in your nail beds, and is more apparent in dark-skinned people.
A condition called Raynaud’s phenomenon can cause your feet to turn whitish blue. If you have this condition, cold temperatures or even strong emotions can cause your blood vessels to spasm, which blocks the blood flow to your feet, toes, ears, nose and fingers.
Other Medical Conditions
Additional medical conditions that can lead to discoloured feet and other body parts include pulmonary hypertension; hyaline membrane disease, which can occur when an infant is born prematurely; pneumonia; bronchiolitis; and COPD or chronic obstructive pulmonary disease. A blood clot in your lung arteries, which is called a pulmonary embolism, can also result in discoloured skin.
If your feet are frostbitten, they will become discoloured.
The Cleveland Clinic notes that ulcers can cause skin discolouration as well as a rash, redness, burning and itching.