Causes of Glomerulonephritis
Glomerulonephritis is commonly due to a problem with the body's immune system. Usually, the immune system works to protect the body against things like infections by attacking and killing the germs causing them. However, sometimes the body's immune system can go wrong. Many cases of glomerulonephritis are caused by the body mistakenly attacking itself, causing damage to the glomeruli of the kidney. It is not always clear why this happens but, in some cases, a trigger can be identified, such as an infection. The infection triggers the problem with the immune system and the damage to the glomeruli.

Infection with certain types of streptococcal germs (bacteria) is the most common infection that can trigger glomerulonephritis. This can happen after an upper respiratory tract infection or a skin infection that was caused by those bacteria. Symptoms of glomerulonephritis typically develop between one and three weeks after the initial infection. Other bacteria, viruses, parasites or fungi can also trigger glomerulonephritis. Glomerulonephritis that is triggered by an infection may occur at any age but it most commonly develops in children aged between 5 and 15 years.

Glomerulonephritis can also be triggered after taking certain medicines, including non-steroidal anti-inflammatory drugs (NSAIDs). In some people, it may be difficult to find a trigger for, or the exact cause of, glomerulonephritis.