A Rare Case of Axial Spondyloarthritis with IgA Vasculitis.

Spondyloarthritis (SpA) is a chronic inflammatory disease characterized by axial, peripheral, and extra-musculoskeletal manifestations. Axial involvement manifests as sacroiliitis, spondylitis, and peripheral involvement in the form of arthritis, enthesitis, and dactylitis. The extra-musculoskeletal manifestations commonly include uveitis, inflammatory bowel disease, and psoriasis, in addition to rare manifestations such as aortitis, interstitial lung disease, immunoglobulin A (IgA) nephropathy, and renal amyloidosis. IgA vasculitis is an immune complex mediated vasculitis affecting small vessels with characteristic IgA deposition within the vessel walls. It primarily affects children and can affect adults in about 10% of cases. A 25-year-old male, diagnosed with nonradiographic axial SpA with bilateral sacroiliitis and enthesitis, presented with recurrent episodes of purpuric skin rash, abdominal pain, loose stools, and pedal edema. On evaluation, he had hypertension and nephritic-range proteinuria. Histopathology of skin lesions and renal biopsy revealed IgA deposits suggestive of IgA vasculitis. To date, only four case reports of SpA and IgA vasculitis have been described in the literature. In a patient with long-standing SpA, the possibility of IgA vasculitis should be considered.