Hypocomplementemic urticarial vasculitis occurring in a patient with relapsing polychondritis

A 36-year-old woman presented with a 6-month history of flares of tense and fixed urticaria involving the limbs and the trunk. The eruption was associated with intermittent fever, facial angioedema, and diarrhea. Past medical history was significant for bilateral perceptive hearing loss, two episodes of tender and swollen ear (right then left ear), recurrent painful redness involving the right then the left eye with blurred vision, and hoarseness. Physical examination revealed pink and painful wheals in the legs (Fig. 1) and inflammation of the cartilaginous portion of the right auricula that spared the lobule (Fig. 2). Ophthalmological examination was unremarkable. Laboratory tests showed elevated ESR and polyclonal hypergammaglobulinemia. A search for cryoglobulins was positive with polyclonal IgG-IgM pattern. Seeking for antinuclear antibody, anti-neutrophil-cytoplasmic antibodies, and rheumatoid factor was negative. Repeated screening for hepatitis B virus, hepatitis C virus, and HIV was also negative. CH50 was inferior to 10 (N > 43), C4 was 10 mg/L (19 < N < 39), and C3 was normal. A search for anti-C1q antibodies was positive. A full work-up for internal malignancies was negative. Histopathological examination of two separate skin biopsies revealed leukocytoclastic vasculitis which was consistent with the diagnosis of HUV. Biopsy of the auricular cartilage was Figure 1 Pink urticarial plaques in the legs associated with pigmented postinflammatory lesions