GED Science TestLife ScienceEasy
A patient experiences a sudden, severe allergic reaction after consuming a food item. Symptoms include widespread hives, swelling of the face and throat, difficulty breathing, and a rapid drop in blood pressure. Which type of immune response is most likely occurring?
- AType III Hypersensitivity (Immune Complex)
- BType I Hypersensitivity (Anaphylactic)
- CType II Hypersensitivity (Cytotoxic)
- DType IV Hypersensitivity (Delayed-Type)
Show answer & explanationAnswer & explanation
Correct answer: B. Type I Hypersensitivity (Anaphylactic)
The symptoms described, including widespread hives, swelling, difficulty breathing, and a rapid drop in blood pressure, are characteristic of anaphylaxis, which is a severe, systemic Type I hypersensitivity reaction. This type of reaction is immediate and can be life-threatening.
Why the other options are wrong
- A. Type III hypersensitivity involves immune complex deposition, leading to inflammation in tissues, not typically immediate widespread anaphylactic shock.
- C. Type II hypersensitivity involves antibody-mediated destruction of cells, not widespread systemic reactions to allergens.
- D. Type IV hypersensitivity is a delayed cell-mediated response, occurring hours to days after exposure, unlike the immediate reaction described.
Type I Hypersensitivity
An immediate allergic reaction mediated by IgE antibodies, often leading to symptoms like hives, swelling, and in severe cases, anaphylaxis.
- Mediated by IgE antibodies
- Rapid onset (minutes)
- Can be localized or systemic (anaphylaxis)
Memory trick: ACID: Anaphylactic, Cytotoxic, Immune-complex, Delayed