Erythromelalgia

Erythromelalgia is a rare clinical syndrome characterized by a triad of redness, warmth, and burning pain, most notably affecting the extremities. It usually affects the lower extremities (most commonly feet) or may involve upper extremities (hands) in few cases. The episodes are typically precipitated by exercise and relieved by cooling the affected parts. Although erythromelalgia is typically bilateral, it can present unilaterally, especially in secondary cases. Atypical cases presenting with lesions and symptoms solely involving the face have been observed; however, they are extremely rare and are often misdiagnosed. Other terms used to describe erythromelalgia are burning feet syndrome, erythermalgia, Gerhardt disease, and Mitchell disease.

The term erythromelalgia is derived from the Greek words erythros, meaning "red," melos meaning "limb," and algos meaning "pain." It was first described in 1878 by Silas Weir Mitchell and was initially termed "Mitchell Disease." Smith and Allen proposed another term, erythermalgia, in 1938 to emphasize the characteristic warmth of this syndrome. Two gentlemen from the Netherland by the names of Drenth and Michiels proposed the name erythromelalgia in 1990.

Classification

The term erythromelalgia and erythermalgia were differentiated on the basis of responsiveness to aspirin by Drenth and Michiels, and the following three categories were established:

(a) Erythromelalgia in thrombocythemia: It is platelet mediated and aspirin responsive. This occurs in association with essential thrombocytosis and polycythemia vera.

(b) Primary erythermalgia: Refers to an idiopathic or inherited disorder. Also called aspirin-resistant erythermalgia of unknown origin.

(c) Secondary erythermalgia: Aspirin resistant and associated with different medical conditions.