Erythromelalgia and Ischemic foot are caused by blood vessels and blood flow issues in the feet.  Both of these conditions need immediate medical care.

Erythromelalgia

Erythromelalgia is a rare disorder that includes enlargement of the blood vessels in the feet.

The blood vessels are open or dilated and the oxygen and heat of the blood is discharged into the tissues, making them turn red and feel hot all the time.

Ischemic Foot

Ischemic foot refers to a lack of adequate arterial blood flow from the heart to the foot.

There are a wide variety of possible causes, including arterial blockage from cholesterol deposits, arterial blood clots, arterial spasm, or arterial injury.

An ischemic foot suffers from an inadequate blood supply reaching the foot to provide the oxygen and nutrient needs required for the cells to continue to function.