Hypersensitivity

Question 1

Describe type I hypersensitivity

Answer 1

• Allergy
• IgE mediated
• Immediate
• Genetically hypersensitive T(helper) cells

Question 2

Rx for type I hypersensitivity

Answer 2

• Antihistamines
• Corticosteroids
• Adrenaline
• Allergen avoidance

Question 3

Describe atopic dermatitis

Answer 3

• Eczema
• Exposed + flexor surfaces
• IgE involved
• “Leaky” skin allows more allergen in and water out

Question 4

Describe type II hypersensitivity

Answer 4

• Cytotoxic (directed to RBC)

- Diagnosed by Coomb’s test

Question 5

Describe type III hypersensitivity

Answer 5

• Anitgen-antibody/immune complex formation
• Deposition in tissues
• Activates phagocytes, causing damage
• “Self-reactive” B/T-cells circulate

Question 6

In type III hypersensitivity what is deposited in tissues and why does it cause damage

Answer 6

• Complexes
• Too small for macrophages to clean them up
• Complement is activated, causing inflammation

Question 7

Example of type III hypersensitivity

Answer 7

Systemic Lupus Erythematosis

Question 8

Describe type IV hypersensitivity

Answer 8

T-cell mediated

Question 9

Example of type IV hypersensitivity

Answer 9

Contact dermatitis

Question 10

Describe contact dermatitis

Answer 10

• Inflammation of the skin.

- Due to exposure to allergens or irritants

Question 11

Rx for contact dermatitis

Answer 11

• Topical steroid

- Allergen avoidance