HighlightsEosinophilic cystitis is a disease of unknown aetiology, however there is an association with a history of allergies and atopy.Common presentations are urinary frequency, dysuria, haematuria, and suprapubic pain, leading to diagnosis of less sinister urinary causes such as urinary tract infections.Natural history is difficult to predict, varying from acute self-resolving cases to chronic debilitating conditions requiring hospital admissions and radical interventions.It is difficult to distinguish from other forms of cystitis and biopsy is necessary for diagnosis.Treatment can vary from medical to operative intervention, or a combination of both.