Erythema elevatum diutinum and hypothyroidism: coincidence or causal relationship?

Erythema elevatum diutinum is a rare chronic leukocytoclastic vasculitis of unknown etiology. It is believed to be due to deposition of immune complexes in the vessels. Clinically it is manifested as erythematous violaceous papules and nodules, isolated or confluent with hardened consistency, symmetrical, usually located on the extensor surface of the extremities, particularly over the joints.