We report two cases of Lyme disease-associated glomerulonephritis. A 57-year-old female presented with rash, volume overload, hypertension and rapidly progressive glomerulonephritis. Biopsy confirmed an immune complex-mediated, membranoproliferative lesion. She was treated successfully with steroids and antibiotics. In a second case, a 40-year-old male, with a previously known microscopic hematuria, presented with rash, arthralgias, new proteinuria and gross hematuria following a tick bite. Biopsy revealed focal proliferative IgA nephropathy. Treatment with steroids and antibiotics resulted in rapid resolution of findings. Acute Lyme disease may contribute to the development of de novo, or activation of previously quiescent, immune-mediated glomerular disease.
