Hypocomplementemic urticarial vasculitis syndrome (HUVS) is a rare type III hypersensitivity disorder characterized by urticarial vasculitis and prolonged hypocomplementemia. Individuals with HUVS may also have joint involvement, pulmonary manifestations, ocular disease, kidney inflammation, or any other form of organ involvement. Hypocomplementemia, the presence of C1q antibody in the serum, and urticarial vasculitis are the keys to the diagnosis of HUVS. It has been reported to accompany certain infections such as hepatitis B, hepatitis C, infectious mononucleosis, and coxsackie group A. However, it has never been reported to be linked to histoplasmosis in the literature. To the best of our knowledge, we report the first case of HUVS presenting concurrently with pulmonary histoplasmosis.

Immunoglobulin G4–related disease (IgG4-RD) is a chronic fibrosing inflammatory systemic disorder that has been recognized relatively recently in the medical literature. Little is known about the exact disease pathogenesis and epidemiology. IgG4-RD may be asymptomatic or may have minimal symptoms or involve multiple organs with overt symptoms. The different phenotypes of IgG4-RD can lead to delayed or incorrect diagnosis. We report the case of a 66-year-old male with coal worker’s pneumoconiosis who presented with progressive kidney disease and was diagnosed with tubulointerstitial nephritis due to IgG4-RD. The patient was noted to have progressive kidney disease, skin involvement, worsening interstitial lung disease, complete vision loss in the left eye, and retroperitoneal fibrosis. Serologic workup revealed elevated inflammatory markers, IgG4 and IgG1 levels, and hypocomplementemia. A tissue biopsy helped us establish a definitive diagnosis of IgG4-RD and initiate treatment with glucocorticoids to prevent further progression of kidney disease and other end-organ damage.