Anaphylaxis and Anaphylactoid Reactions

Diagnosis/Definition:

Any severe allergic reaction to proteins, medications, insect venoms, and a variety of other stimuli manifested by potentially life threatening symptoms such as hypotension, bronchospasm, and laryngeal edema.

Initial Diagnosis and Management

• A reliable history of respiratory distress, hypotension or symptoms typical of hypotension such as loss of consciousness or near syncope, after an exposure to a foreign substance. Exposure may be by ingestion, contact, or parenteral injection. There are occasional instances of identifiable co-factor such as food ingestion. Historical evidence alone will suffice to justify referral.
• Aggressive treatment with epinephrine, airway management as necessary, volume expansion, and use of pressors as necessary. Corticosteroids can prevent a rebound reaction.

Ongoing Management and Objectives

• Following discharge from acute care, all individuals should have an Epi-pen in their possession whenever there is a possibility of subsequent exposure to whatever caused anaphylaxis. This would typically be the case with venom reactions, food reactions, exercise induced anaphylaxis, and idiopathic anaphylaxis. Drug reactions, on the other hand, are inherently more avoidable and would not commonly suggest the need for immediate self-resuscitation. Each individual given an epinephrine kit should be given competent instruction on both when and how to use it.
• Medical records should be appropriately annotated with the information on the known allergies and medical warning jewelry or written documentation should be carried on the person.

Indications for Specialty Care Referral

Need to precisely identify what caused the reaction to enhance avoidance or to desensitize. Desensitization has been reliably performed for hymenoptera stings. Food desensitization is not practiced because of its inherent dangers.

Large local reactions to hymenoptera stings without any historical evidence for anaphylaxis should not be referred.

Drug desensitization may be performed by the allergist for certain drugs (mostly antibiotics).

Criteria for Return to Primary Care

Completion of the initial evaluation, unless desensitization is begun.

Hymenoptera desensitization may last for 3-years or longer. Once such a course is completed, the patient can be returned to primary care for that condition.

Patients may be referred immediately back to primary care following drug desensitization. Most of such desensitizations are not permanent, which may necessitate future referral.