[Acute interstitial nephritis caused by drug hypersensitivity.  Current controversies]. 
Acute interstitial nephritis (AIN) due to drug hypersensitivity represents 0.8 to 8 p. 100 of all causes of acute renal failure.  Two thirds of cases are due to antibiotics, mainly beta-lactamines, and to non-steroidal anti-inflammatory drugs.  Blood hypereosinophilia, fever, arthralgias and/or hepatocellular damage are suggestive of an allergic drug reaction in patients with AIN, with a sensitivity of 0.75 and a specificity of 0.76.  Examination of an early renal biopsy specimen is a clue to the diagnosis of AIN due to drug hypersensitivity if it discloses a diffuse or focal interstitial infiltration with lymphocytes, plasma cells, and mainly by eosinophils and/or epithelioid cell granulomas.  These findings suggest a delayed hypersensitivity reaction, although many cases seem to be also mediated by humoral immune factors.  Renal recovery is frequent when the responsible drug is promptly withdrawn.  The value of steroid therapy in preventing residual renal damage has to be assessed by controlled studies.