This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Immunology, Subject name: Microbiology
Skin test demonstrates all types of hypersensitivity except: 
Select and explain. 
A. Type 1, B. Type 2, C. Type 3, D. Type 4
B: Type 2
Answer: B: Type 2 
Explanation: Ans: b (type 2)Ref: Kuby's Immunology, 6th ed. Pg. 371-396.Hypersensitivity* Type I hypersensitivity - Ig E mediated- Causes systemic anaphylaxis and localized atopy- Detection includes skin testing by intradermal injection or by superficial scratching which helps in screening of allergens* Type II hypersensitivity- antibody mediated cytotoxicity- Causes transfusion reactions, haemolytic disease of newborn, drug induced haemolytic anaemia etc- No skin test is used for detection* Type II hypersensitivity- immune complex mediated- Causes arthus reaction and serum sickness- It can be as a result of injection of antigen* Type IV hypersensitivity - delayed type- Contact dermatitis, granuloma etc- Can be detected by skin tests and patch tests.