Hypocomplementemic Urticarial Vasculitis with Crescentic Glomerulonephritis, Interstitial Nephritis and Small Vessel Vasculopathy: Case Report and Mini-Review

Hypocomplementemic urticarial vasculitis (HUV) is the rare immune complex vasculitis, affecting small vessels and associated with anti-C1q antibodies, presenting with urticaria and hypocomplementemia. Glomerulonephritis, arthritis, obstructive pulmonary disease, and ocular inflammation are common in HUV. HUV may present as an idiopathic disease or be a part of systemic autoimmune or autoinflammatory condition, like systemic lupus erythematosus, arthritis-hives-angioedema (AHA) syndrome, cryoglobulinemic vasculitis, Schnitzler syndrome, Cogan’s syndrome and Muckle–Wells syndrome. Renal involvement includes proteinuria, sometimes of nephrotic range, hematuria and usually moderately impaired kidney function. Various pathology variants were found in patients with HUV: mesagnial proliferative, membranoproliferative, focal proliferative, membranous, minimal change, crescentic and severe sclerosing proliferative glomerulonephritis. Interstitial nephritis and C1q-associated small vessel vasculopathy are poorly described. Here we present a case of HUV with combined renal damage crescentic glomerulonephritis, interstitial nephritis and small vessel vasculopathy, successfully treated with immunosuppressant’s, and discuss the differential diagnostics of HUV.