Erythromelalgia

Erythromelalgia, also called Mitchell's disease after the physician who first described it, is a rare disorder of the peripheral blood vessels marked by episodes of intense burning pain, redness and warmth, most often in the feet and hands. Attacks are periodic and are commonly brought on by heat, pressure, mild activity, exertion, insomnia or stress, and they involve temporary blockage of small blood vessels followed by a rush of blood flow and inflammation. The primary form of the disease has been traced to mutations in the SCN9A gene, which codes for a voltage-gated sodium channel called NaV1.7 found in pain-sensing nerve fibers; identifying this link in 2004 marked the first time a human pain disorder had been tied directly to a mutated ion channel. Secondary erythromelalgia can also arise from other conditions, including blood disorders such as polycythemia vera, certain medications, or poisoning.