Hypocomplementic Urticarial Vasculitis Syndrome

Hypocomplementemic Urticarial Vasculitis (HUV) is a rare vasculitis syndrome which was recognized in 2012 and was revised in the International Chapel Hill Consensus Conference (CHCC). It is defined as presence of greater than six months of urticaria along with hypocomplementemia and multi-systemic manifestations such as recurrent abdominal pain, uveitis, arthralgia and glomerulonephritis. It is often associated with obstructive pulmonary diseases such as emphysema, a major source of morbidity and mortality. Diagnosis of HUV is made by the presence of antibodies against the complement protein 1q and skin biopsy. Histopathologically, it is a small vessel disease with perivascular infiltration of neutrophils. HUV syndrome is also associated with systemic lupus erythematosus (SLE) and has multiple overlapping features. HUV syndrome could also be an initial presentation of SLE. However, angioedema, COPD, and uveitis are more common in HUV syndrome compared to SLE. HUV is a benign selflimited vasculitis but has a considerable morbidity burden. Thus, early screening of urticaria patients is recommended, especially those having dyspnea and proteinuria.