Eosinophilic cystitis.

Eosinophilic cystitis is an uncommon inflammatory disease of the urinary bladder characterized by irritative urinary symptoms and eosinophilia of the involved tissue and often of the peripheral blood. Parasitic bladder infiltration has been suggested as the etiologic agent, but review of the literature revealed only one case in which this was proven. A 3.5-year-old boy with eosinophilic cystitis was extensively investigated, but there was no evidence of parasitism. Several immunologic reactions may cause eosinophilia in both tissues and peripheral blood, but no specific allergen could be found in this patient.