What does the presence of eosinophils in urine suggest?

The presence of eosinophils in urine is most commonly indicative of an allergic reaction or drug-induced interstitial nephritis. Eosinophils are a type of white blood cell that often increase in response to allergic reactions and certain infections, particularly those involving the kidneys. In cases of drug-induced interstitial nephritis, medications can trigger an immune response leading to the accumulation of eosinophils in the renal interstitium, which can then be reflected in the urine.

The detection of eosinophils in urine typically arises during urinalysis when assessing for conditions associated with allergies or hypersensitivity reactions affecting the kidneys. This finding assists clinicians in diagnosing renal issues related to drug exposure or allergic processes rather than other acute conditions such as infections, dehydration, or kidney failure. Therefore, finding eosinophils serves as a crucial diagnostic clue pointing towards interstitial nephritis rather than infections or dehydration.