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Management of Anaphylactic reaction (Type 1 Hypersensitivity Reaction)

August 31, 2026Immune systemLab Tests

Anaphylactic reaction

What is the mechanism of an anaphylactic reaction?

How will you define anaphylactic reaction?

  • Type 1 hypersensitivity reaction is an immediate and IgE-mediated hypersensitivity reaction.
  • It is triggered when IgE antibodies are produced, which will activate mast cells and basophils.

What is the initiator of the anaphylactic reaction?

  1. It may be observed in a patient during or after a blood sample is taken.
  2. This reaction may occur due to trauma, pain, or an unusual situation.
  3. So every technician and every ordinary person should know how to handle such a situation.
  4. First, try to understand how these patients will present

What are the stages of a type 1 hypersensitivity reaction?

  1. First stage:
    1. An allergen stimulates B lymphocytes and activates Th-2 cells.
    2. Th-2 helper cells produce interleukin-4 and interleukin-13.
    3. B lymphocytes produce IgE.
  2. Second stage:
    1. IgE antibodies attach to FcεR on mast cells and basophils.
    2. IgE antibodies cross-link and release chemical mediators.
IgE receptor

IgE receptor

What are the chemical mediators in a type 1 hypersensitivity reaction?

  1. Important mediators are:
    1. Histamine.
    2. Leukotrienes.
    3. Prostaglandins.
    4. Cytokines.
    5. Tryptase.
  2. Preformed mediators are:
    1. Histamine.
    2. Heparin.
    3. Tryptase.
  3. Secondary mediators are:
    1. Leukotrienes (LTC4, LTD4, LTE4).
    2. Cytokines.
    3. Prostaglandins D2.
IgE antibody, mast cell, and Basophil

IgE antibody, mast cell, and Basophil

What are the effects of chemical mediators?

  1. Vasodilatation.
  2. Increased vascular permeability.
  3. Itching.
  4. Increased mucous secretion.
  5. Bronchospasm.

What are the examples of type 1 Hypersensitivity?

  1. Allergic asthma.
  2. Anaphylaxis.
  3. Urticaria (hives).
  4. Food allergies.
  5. Drug allergies.

What are the phases of a type 1 hypersensitivity reaction?

  1. Immediate phase:
    1. It occurs in minutes.
    2. It is due to histamine released by the mast cells.
  2. Late phase reaction:
    1. It usually occurs after 2 to 24 hours.
    2. This may involve eosinophils.

How will you compare all types of immune reactions?

Type of hypersensitivity reaction Mechanism Type of immune cells Immune components Clinical presentation
  • Type 1 reaction
 Immediate immune reaction B- lymphocytes
  1. IgE
  2. Mast cells
  3. Basophils
  1. Anaphylactic reaction
  2. Hay fever
  3. Asthma
  • Type 2 reaction
  1. Antibodies attack cells
  2. Antibody attack tissues
 B-lymphocytes
  1. IgG
  2. IgM
  1. Goodpasture syndrome
  2. Autoimmune hemolytic anemia
  • Type 3 reaction
  1. Immune complexes
  2. Immune complex deposition in various organs
 B-lymphocytes
  1. IgG immune complexes
  2. IgM immune complexes
  1. Serum sickness
  2. SLE
  3. Autoimmune diseases
  • Type 4 reaction
  1. Delayed cell-mediated
 T-lymphocytes Cell mediated
  1. TB skin test
  2. Contact dermatitis

 What will be the presentation of the Anaphylactic reaction?

The patient will show the following:

  1. Nervousness.
  2. Itching of the skin.
  3. The feeling of confusion.
  4. Nausea, vomiting, and diarrhea.
  5. Abdominal or back pain.
  6. There will be flushing, pallor, or cyanosis.
  7. Urticaria.
  8. Laryngeal edema leads to stridor.
  9. Tachycardia.
  10. There is low blood pressure.
  11. Convulsions.
  12. Respiratory depression.
  13. Bronchospasm leads to asthmatic attacks.

How will you handle such a person with an Anaphylactic reaction?

  1. Immediately perform the following measures:
    1. Stop the blood sample process.
    2. Lie the patient flat and raise the legs.
Anaphylactic reaction: Blood collection complications

Anaphylactic reaction: Blood collection complications

    1. Maintain the airway.
    2. Call the doctor for help.
    3. Give an antihistamine injection or Decadron (hydrocortisone).
    4. Give oxygen if needed.
    5. Give cardiopulmonary resuscitation if needed.
  • If the patient does not improve, transfer the patient to the hospital.
  • This article is written for lab technicians and the general public. This will be helpful to everybody.

The following diagram summarises the anaphylactic reaction.

Anaphylactic reaction: Type 1 Hypersensitivity reaction

Possible References Used

Possible References Used
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