Question

Arthus reaction and Serum sickness is an example of
A. Hypersensitivity reaction I
B. Hypersensitivity reaction II
C. Hypersensitivity reaction III
D. Hypersensitivity reaction IV

Answer 1

Hint: Hypersensitivity also called hypersensitivity reaction or intolerance refers to undesirable reactions produced by the normal immune system, including allergies and autoimmunity.
Allergens are the allergy producing substances that can be pollen grains, certain food, or dust..

Complete answer:
 In order to solve this question we need to learn more about allergy and hypersensitivity reactions.
Allergy: Allergies also known as allergic diseases are a number of conditions caused by hypersensitivity of the immune system to t harmless substances in the environment.
These diseases may include food allergies, atopic dermatitis, allergic asthma, and anaphylaxis.
Symptoms may include
1. Red eyes
2. An itchy rash
3. Sneezing
4. A running nose
5. Shortness of breath
6. Swelling.
Common allergens include pollen and certain foods.
Food, insect bite and medications are common causes of severe reactions.
Hypersensitivity: Hypersensitivity reactions are an overreaction of the immune system to an antigen which would not normally trigger an immune response.
There are four types of hypersensitivity reactions:
1. Hypersensitivity reaction I
2. Hypersensitivity reaction II
3. Hypersensitivity reaction III
4. Hypersensitivity reaction IV

Hypersensitivity reaction I: Immediate Hypersensitivity also known as Anaphylactic Reaction.
These allergic reactions are systemic or localized (e.g., hives, wheal and erythema reactions).
Hypersensitivity reaction II: It is a Cytotoxic Reaction (Antibody-dependent).
Hypersensitivity reaction III: It is an Immune Complex Reaction.
The excess of antigen agglutination leads to the formation of small immune complexes and are not cleared from the circulation.
When these antigens agglutinate and insert themselves into small blood vessels, joints, and glomeruli, causing severe symptoms.
Arthus reaction is caused due to the formation of antigen antibody complex which causes an inflammatory response.
Serum sickness is also caused due to hypersensitivity created by antigen - antibody complex.
Hypersensitivity reaction IV: It is a Cell-Mediated or Delayed Hypersensitivity Reaction.

So, the correct option is, option c. Hypersensitivity reaction III.

Note: Anaphylaxis is a serious, life-threatening allergic reaction. The most common anaphylactic reactions are to foods, insect stings, medications and latex.
If you are allergic to a substance, your immune system overreacts to this allergen by releasing chemicals that cause allergy symptoms.
Risk factors are asthma and allergen.
It is a type I hypersensitivity reaction.