Hypocomplementaemic urticarial vasculitis

**Definition:** Vasculitis accompanied by urticaria and hypocomplementemia affecting small vessels (i.e., capillaries, venules, or arterioles), and associated with anti-C1q antibodies. Glomerulonephritis, arthritis, obstructive pulmonary disease, and ocular inflammation are common.(Chapel Hill Consensus Conference, 2011)