Anaphylaxis is an acute, life threatening event that can progress extremely rapidly. External allergens as causations have been identified over the last century. The most recently identified type of anaphylaxis is not caused by any external allergen and has been termed Idiopathic Anaphylaxis (IA). Two major types are Generalized or Angioedema with airway obstruction. IA is also classified by frequency of episodes and response to therapy. Therapy consists of acute emergency therapy and induction of remissions using prednisone, beta agonists, and H1 blockers. Control and remission are usually induced. IA occurs at all ages, and pediatric and geriatric IA are often special problems, as is a psychogenic form where no true reactions occur. Although appropriate management of IA, in general, has a good prognosis, several problems exist. Among these are failure to accept IA as an entity or in an individual case by physicians and patients. A different problem occurs when the recommended treatment is used and there is control of IA, but only with persisting high doses of prednisone. This is corticosteroid dependent IA. The lack of defined mechanisms that will lead to improved therapies and wider acceptance of IA as an entity remains a major problem. Undifferentiated Somatoform IA is a serious management problem for physicians.