[Nephropathy associated with hypocomplementemic urticarial vasculitis: A case report and literature review]

Hypocomplementemic urticarial vasculitis is a rare systemic vasculitis, affecting small vessels, characterised by chronicle urticaria, hypocomplementemia, and systemic manifestations. Renal involvement, whose prevalence varies between 9% and 60%, is mainly glomerular. We here report the case of a 59 years old woman presenting kidney failure, associated with chronicle urticaria and arthralgias. Laboratory investigation showed haematuria, proteinuria, hypocomplementemia and anti-SSa antibody positivity. A percutaneous kidney biopsy revealed focal and segmental glomerulonephritis associated with an acute interstitial nephritis. Hypocomplementemic urticarial vasculitis diagnosis was established after identifying anti-C1q antibodies. The lack of a dry syndrome, the negativity of a Schirmer test and the lack of sialadenitis on a salivary gland biopsy excluded an associated Gougerot-Sjögren Syndrome. The patient was treated with hydroxychloroquine and low-dose steroids, enabling a clinical and biological recovery. Of the 82 cases in the literature describing hypocomplementemic urticarial vasculitis associated nephropathies, 72 (88%) were a glomerular impairment, most frequently secondary to membranoproliferative glomerulonephritis. Only 6 (7%) tubulo-interstitial nephritis have been reported, 4 of them being associated with a glomerulonephritis. Patients were more likely to be women, aged in their third decade. The most frequent renal manifestations were haematuria (60%), and proteinuria (52%). Kidney failure was rarely observed (22%), with a fairly good renal prognosis. Hypocomplementemic urticarial vasculitis was associated with a systemic disease in 11 (13%) patients. In the absence of recommendations, the treatment strategy remains to be defined.