Hypocomplementemic urticarial vasculitis
(HUV) is a rare form of cutaneous small-vessel vasculitis characterized by recurrent episodes of urticaria and painful, tender, burning or itchy skin lesions, often associated with extracutaneous involvement but usually with no significant peripheral nerve damage. Patients with this condition are likely to have systemic involvement, including angioedema, arthralgias, pulmonary disease, abdominal or chest pain, fever, renal disease, and episcleritis. Hypocomplementemic urticarial vasculitis is thought be an autoimmune response involving a specific region of complement 1 (C1). It can present as or precede a syndrome that includes obstructive pulmonary disease , uveitis, systemic lupus erythematous (SLE), Sjšgren's syndrome, or cryoglobulinemia (which is closely linked with hepatitis B or hepatitis C virus infection). Some cases of hypocomplementemic urticarial vasculitis respond to therapies commonly used for the treatment of SLE, including low-dose prednisone, hydroxychloroquine, dapsone, or other immunomodulatory agents. Source: Genetic and Rare Diseases Information Center (GARD), supported by ORDR-NCATS and NHGRI.