Feet turn black in peripheral gangrenous changes, in diseases of arteries which lack to supply blood distally, due to insufficiency.e.g.DIABETIC FOOT .
Feet turn blue in Peripheral cyanosis, in cardiovascular diseases , especially in children,in arterial insufficiency to regulate oxygenated blood to the distal extrimities. E.g. TETRAD OF FALLOT.
Local area bruising and broken capillaries or poor circulation. Gangrene. Frostbite. Mineral deposits from sweating. Dyes from shoes and/or socks. Diabetes. Black-Spot Poison Ivy dermatitis (rare).
100,000 feet.
Fingers and feet turn blue in the elderly because these individuals have poor circulation. The blue color is the effect of the area becoming cold.
red and blue makes black
Silver Nitrate does not turn blue - it turns purple-black and then black. It was the basis for early photography before the digital age.
If you are wearing black or blue socks, wash your socks in hot water to get rid of the excess dye. Or perhaps your shoes are too tight. If that's not it, then you should see a doctor. Tomorrow. Maybe even tonight.
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turn blue
blue
Your feet turn blue-purple when they do not get enough blood flow or when they are lacking circulation or some times they are cold the best thing to do is rub them or run them under warm water.
blue
blue/black
Feet can turn black due to a condition known as gangrene, which is caused by a lack of blood flow and oxygen to the tissues. This can be a result of severe infections, diabetes, or peripheral artery disease. It is important to seek medical attention promptly if you notice any changes in the color of your feet.