Anaphylaxis

Disease Description (Causes and Symptoms)

Anaphylaxis is a systemic, acute hypersensitivity reaction to specific antigens (such as foods, medications, or bee venom) that develops rapidly and causes symptoms affecting multiple organs, including the skin (rash and itching), respiratory system (shortness of breath, wheezing, and cough), cardiovascular system (hypotension, tachycardia, and decreased consciousness), and digestive system (vomiting and abdominal pain). Pathophysiologically, when exposed to an antigen, histamine, tryptase, and various mediators are released from mast cells and basophils through immediate-type (IgE-mediated) or non-IgE mechanisms, causing vasodilation, increased vascular permeability, and bronchoconstriction. Symptoms usually appear within 1 hour of exposure, and life may be threatened if hypotension and breathing difficulties progress.

Examples of major symptoms: rash, hives, skin itching, tingling in the mouth or hands and feet, cough, shortness of breath, wheezing, chest pain, vomiting, abdominal pain, hypotension, decreased consciousness, and tachycardia.

Treatment Methods

• Emergency treatment (perform immediately)
  • Intramuscular injection of epinephrine (adrenaline) (IM, into the deltoid/mid-outer thigh)
    • Adults: 0.3–0.5 mg (1:1,000, 1 mg/mL) IM; may be repeated every 5–15 minutes as needed
    • Children: 0.01 mg/kg (maximum 0.3 mg) IM; follow the instructions for weight-based auto-injectors (0.15 mg/0.3 mg)
  • Secure the airway and provide oxygen (high-flow oxygen)
  • Large-volume fluid administration (intravenous fluids in cases of hypotension) and, if necessary, vasodilators/blood pressure-raising agents (IV epinephrine or norepinephrine)
  • Inhaled beta-2 agonists (nebulizer) for bronchospasm
  • Antihistamines (H1); H2 blockers may be used as an adjunct in some cases
  • Glucocorticoids (used to prevent recurrence or delayed reactions, but they have no immediate effect)
  • If there is airway edema or emergency intubation is needed, airway management (intubation or preparation for emergency airway access)
• Additional management
  • Observation: Observe for at least 4–6 hours depending on symptom severity; consider observation for 24 hours or longer in severe cases or when repeated epinephrine administration, hypotension, beta-blocker use, or other factors are present (secondary recurrence is possible)
  • Diagnostic support: Serum tryptase testing within 1–3 hours immediately after symptom onset can confirm mast cell activation (diagnostic support)
  • Identifying the cause: After referral to an allergist, identify the cause through skin testing, specific IgE testing, and provocation testing (in a safe environment), among other methods
  • Education: Prescribe an epinephrine auto-injector and provide training on its use; after recovery, arrange follow-up with an allergist and prepare a personalized emergency response plan
  • Preventive treatment: Depending on the cause, consider avoiding the food, substituting the medication, or immunotherapy for bee venom allergy (bee venom immunotherapy)
• Precautions · Complications · Self-care
  • Always visit the emergency department immediately after self-injecting epinephrine (additional treatment and observation are necessary)
  • People taking beta-blockers may have an inadequate response to epinephrine; in such cases, consider administering glucagon
  • Some medications, including MAO inhibitors, may affect the response to epinephrine
  • Complications: hypoxic brain injury, impaired organ function due to shock, secondary (biphasic) reaction (recurrence within several hours), and death
  • Self-care: Avoid the cause, always carry an epinephrine auto-injector and replace it regularly (check the expiration date), and consider wearing a medical allergy identification tag

Checklist Before an Outpatient Visit (Items to Bring and Example Questions)

Items/materials

• A list of currently used medications (including prescription drugs, over-the-counter medications, and supplements)
• Records of past allergy history (time of reaction, symptoms, and whether treatment was received)
• Records of the onset time of recent symptoms, the substance suspected to have caused the exposure, and the course of symptom progression
• Previous test results (such as specific IgE, skin reaction tests, and tryptase test results) and medical records
• Whether you possess an epinephrine auto-injector and a photo of it (model and expiration date)
• Photos taken during symptoms (such as rashes)
• Possibility of pregnancy/whether pregnant (for women)

Example questions (prepare what to ask the doctor)

• What do you think is the possible cause of this reaction?
• What additional tests are needed (such as specific IgE or skin testing)?
• Can I receive a prescription for an epinephrine auto-injector and training on how to use it in the future?

Examples of General Questions to Ask the Doctor

• What are the expected side effects of this medication (or treatment)?
• What measures should I take to prevent the next attack?
• How long should the observation period be after recovery?
• Could you show me a demonstration of how to use the epinephrine auto-injector?
• I am taking a specific medication (e.g., a beta-blocker). How will treatment differ if anaphylaxis occurs?

Examples of Disease-Specific Questions

• A specific food (or medication/bee venom) is suspected as the cause. What is the procedure for safely identifying the cause (such as through skin testing or provocation testing)? (Including whether any medications must be stopped before testing)
• If I have a bee venom (or specific medication) allergy, do I meet the indications for immunotherapy (e.g., bee venom immunotherapy), and what are its advantages, disadvantages, and success rate?

(Note: In an emergency, epinephrine should be administered without delay, followed by transport to the emergency department. Subsequent coordination with an allergist and identification of the cause are recommended.)