Health & Safety | Lesson 1 | Anaphylaxis
Anaphylaxis, also called allergic or anaphylactic shock, is a sudden, severe and life-threatening allergic reaction that involves the whole body. The reaction is marked by constriction of the airways, leading to difficulty breathing. Swelling of the throat may block the airway in severe cases.
In 1963, two British immunologists, Robert Coombs and Philip Gell, classified four different types of hypersensitivity reactions:
- Immediate (type I)
- Symptoms appear after a few seconds to minutes
- Anaphylactic reactions: the most severe form of allergic reaction
- Anaphylaxis is a medical emergency that can lead to sudden, life-threatening respiratory failure
- Symptoms include difficulty breathing, swelling, low blood pressure, bluish skin, and shock
- IgE antibodies are produced by the immune system in response to allergens such as pollen, animal dander, insect bites, dust mites, or certain foods
- Symptoms appear after a few seconds to minutes
- Cytotoxic (type II)
- Symptoms appear after minutes to hours
- IgG and IgM antibodies damage cells by activating the complement system of the immune system such as in:
- Autoimmune hemolytic anemia
- Immune thrombocytopenia
- Autoimmune neutropenia
- Goodpasture syndrome
- Graves’ disease
- Myasthenia gravis
- Immune complex-mediated (type III)
- Symptoms set in after several hours
- IgM and IgG antibodies react with allergens to form immunocomplexes (antigen-antibody complexes) such as in:
- Lupus
- Serum sickness
- Arthus reaction
- Delayed hypersensitivity (type IV)
- Symptoms set in hours to days later
- Often in long-term infectious diseases such as: