Concomitant IgA nephropathy and dermatomyositis: a case-based review

IgA nephropathy concomitant with dermatomyositis is extremely rare. We describe a 38-year-old male who presented with generalized swelling and scanty red urine followed by proximal muscle weakness and dysphagia. Urinalysis revealed proteinuria, hematuria, and red blood cell casts. Renal biopsy showed IgA deposition in the mesangial tissue of the glomerulus by immunofluorescence technique, compatible with IgA nephropathy. He had no preceding history of respiratory tract infections or associated illnesses like inflammatory bowel disease, ankylosing spondylitis, psoriasis, cirrhosis or IgA vasculitis. The patient was treated with prednisolone and mycophenolate mofetil and within 12 weeks nephropathy and muscle weakness improved, as well as the skin rash. We review the existing literature regarding the concurrence of dermatomyositis and IgA nephropathy. The combination of these disorders in adult patients appears to be extremely rare, to our knowledge this is the third published case. In children there have been published another 3 cases. Although we cannot exclude a co-incidence that two disorders are found in the same patient, it seems more likely that a common pathological mechanism plays a role.