1. Extreme Type I Hypersensitivity Reactions
Anaphylaxis
Extreme Type I Hypersensitivity Reactions

2. Overview Components of type I hypersensitivity
Cause of type I hypersensitivity
Effects of degranulation
Systemic anaphylaxis
Emergency and Post-emergency Treatment

3. Components of Type I Hypersensitivity
Allergen- Antigen (protein) from various sources which causes hypersensitivity reaction in some people
Food, medication, insect products, plant pollen, etc.
Immunoglobulin E (IgE)- Antibodies, normally produced to protect against parasitic infection, instead produced specific to the allergen
Mast cells- Highly granular cells with Fc receptors for IgE
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4. Cause of Type I Hypersensitivity
Allergen antigens affect approximately 10% of the population.
These antigens cause the production of immunoglobulin E (IgE) antibodies.
IgE binds to Fc receptors on mast cells
Upon subsequent exposure, the allergen activates these sensitized cells causing degranulation

5. Cause of Type I Hypersensitivity
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6. Effects of Degranulation
When the granules release their contents, histamine and various leukotrines, into the surrounding tissue during a simple type I hypersensitivity reaction the following results occur:
Smooth muscle cells contract
Small blood vessels dilate
Increase in bronchial mucus secretions
However, anaphylaxis is much more serious

7. Systemic anaphylaxis
Severe, life threatening type I reaction normally starting just minutes after exposure
Symptoms can include:
Cardiovascular: hypotension, chest pain, cardiac arrest, faint pulse and shock

8. Symptoms Continued
Dermatologic: urticaria (hives), swelling, itchy skin, sensation of warmth, flushing, angioedema (rapid swelling) and rash
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9. Symptoms Continued And death
Gastrointestinal: nausea, cramps, vomiting, diarrhea, itchy mouth/throat
Pulmonary: vasodilation of arterioles and constriction of bronchioles in the lungs, respiratory distress, throat tightness, cough, nasal congestion, trouble swallowing, respiratory arrest
And death
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10. Immediate Treatment
Epinephrine (adrenaline) is used to treat severe anaphylaxis. This is an immediate treatment to open the airway and raise the blood pressure
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11. Immediate Treatment If the patient is not breathing perform CPR
In any event contact 911 immediately
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12. Advanced Treatment
Advanced medical treatment by EMTs or ER personnel may include endotracheal intubation
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13. Advanced Treatment
Hypotension is usually treated with IV fluids and “pressors,” drugs that raise the blood pressure
Bronchodilators such as albuterol are used to open the airway
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14. Post-emergency Treatment
After lifesaving measures are successful the hypersensitive reaction must be controlled
Antihistamines like diphenhydramine
Corticosteroids like prednisone
Are given to further reduce symptoms

15. Review Components of type I hypersensitivity
Cause of type I hypersensitivity
Effects of degranulation
Systemic anaphylaxis
Emergency and Post-emergency Treatment