Erythromelalgia

Erythromelalgia, also known as Mitchell's disease (after Silas Weir Mitchell), acromelalgia, red neuralgia, or erythermalgia, is a rare neurovascular peripheral pain disorder in which blood vessels, usually in the lower extremities (or hands), are episodically blocked (frequently on and off daily), then become hyperemic and inflamed. There is severe burning pain (in the small fiber sensory nerves) 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 (i.e. a disorder in and of itself or a symptom of another condition). Secondary erythromelalgia can result from small fiber peripheral neuropathy of any cause, essential thrombocytosis (erythromelalgia can also develop in the presence of normal platelet counts in patients with myeloproliferative disorder), hypercholesterolemia, mushroom or mercury poisoning, and some autoimmune disorders.. Primary erythromelalgia is caused by mutation of the voltage-gated sodium channel α-subunit gene SCN9A.