With oral agents biphasic or prolonged reactions are more common than perceived previously. Glucocorticoids do not reproducibly prevent biphasic or protracted anaphylaxis. Patients with reactions need to be observed for greater than 12 hours especially if upper airway obstruction is involved. Forty percent reaction rate with positive history. Positive minor determinant skin test is associated with anaphylaxis.
Desensitization is possible in a controlled environment.
Non IgE - vancomycin, polymyxins. Immunotherapy is maintained at 100 micrograms per antigen for 60 months. Specific IgE and IgG titers can then help predict continued need for therapy. To document safety of a particular agent provocative skin testing can be performed. Fatalities usually occur in victims with prior knowledge i.e., past anaphylaxis.