A 60-year-old woman with acute asthma developed generalised urticaria and rapidly worsening bronchospasm immediately after IV administration of methylprednisolone sodium succinate. Subsequent skin testing was positive for this, but for no other corticosteroid. Later, both IV dexamethasone during a recurrent attack and oral prednisone for panhypopituitarism were well tolerated. This patient and a review of the literature reveal that corticosteroids are a very rare but important cause of anaphylaxis-like reaction.