Hypocomplementemic urticarial vasculitis: a rare presentation revealing systemic lupus erythematosus and Sjögren's disease.

Hypocomplementemic urticarial vasculitis (HUV) is a rare small-vessel vasculitis that may occur as a primary form or secondary to systemic disease. Its concurrent association with systemic lupus erythematosus (SLE) and Sjögren's disease (SD) remains exceptional. Diagnosis is particularly challenging due to overlapping clinical and immunological features among these entities. We report the case of a 46-year-old woman with no significant medical history, presenting with recurrent chronic urticaria resistant to antihistamines. Clinical, biological, and histological investigations led to the diagnosis of HUV associated with SLE and SD without severe organ involvement. Treatment with colchicine and hydroxychloroquine resulted in complete remission of symptoms. This case highlights the importance of considering HUV in any patient with chronic or refractory urticaria and of systematically screening for associated autoimmune diseases, particularly SLE and SD.