erythromelalgia
A rare neurovascular peripheral pain disorder due to the intermittent blockage of the blood vessels, usually in the lower extremities or hands. This causes hyperemia and inflammation at the origin of burning pain and skin redness. The attacks are periodic and are commonly triggered by heat, pressure, mild activity, exertion, insomnia or stress. Erythromelalgia may occur either as a primary or secondary disorder. Primary erythromelalgia is caused by gene mutations. Secondary erythromelalgia can result from small fiber peripheral neuropathy of any cause, essential thrombocytemia, hypercholesterolemia, mushroom or mercury poisoning, and some autoimmune disorders.