Hypersensitivity reaction to mannitol.

A 60-year-old atopic female was admitted for investigation of progressive neurological deficits involving her left hand, arm, and shoulder. A computed tomography scan demonstrated a right parietal lesion of her brain, which was removed. Increasing intracranial pressure necessitated the administration of mannitol 20% 250 ml. The patient stated she had a "tightness" in her chest during the mannitol administration. Five days later, rises in intracranial pressure again necessitated the infusion of mannitol 20% 150 ml. After 100 ml of the solution had been infused, the patient experienced mild respiratory distress, cyanosed lips, and hives of her abdomen. Supportive therapy, including aminophylline and diphenhydramine administration, abated her distress. Anaphylaxis to mannitol administration has only been reported twice previously, despite mannitol's widespread use. Physicians and pharmacists should be aware that severe hypersensitivity reactions may occur, especially in patients with a history of atopy.