Hypersensitivty reactions

Question 1

What is an allergen?

Answer 1

Any substance that mostly is eaten or inhaled that is recognised by the immune system that causes an allergic reaction

Question 2

What occurs during type I hypersensitivity?

Answer 2

• dilation of blood vessels= decreased vascular resistance then shock
• increased capillary permeability=swelling of local tissues
• constriction of bronchial airways
• stimulation of mucous
• stimulation of nerve endings=itching and pain in the skin

Question 3

What do mast cells and basophils do to help allergic reactions?

Answer 3

They release potent inflammatory mediators,

Question 4

What causes the release of inflammatory mediators from mast cells?

Answer 4

they can be induced (activated to be released) by:

• physical destruction, high temp or mechanical trauma
• chemical substances, toxins and venom
• endogenous mediators, tissue protease
• immune mechanism which may be IgE-dependanct or independant

Question 5

Where are histamines generated?

Answer 5

By the white blood cells and released during an allergic reaction

Question 6

What does type IV hypersensitivity mean?

Answer 6

Delayed reaction

Question 7

What are some examples of type IV hypersensitivity causes?

Answer 7

Contact dermatitis and drug related allergies

Question 8

What drives type I hypersensitivity?

Answer 8

IgE antibodies

Question 9

What drives type IV hypersensitivity?

Answer 9

-cytotoxic T-cells, macrophage and helper T-cell

Question 10

What is the mantoux reaction?

Answer 10

Tuberculin skin test is an example of thus type of reaction to see if you are allergic

Question 11

What does atopic mean ?

Answer 11

Patients prone to IgE-mediated allergic recations

Question 12

What is atopy?

Answer 12

The genetic predisposition to make IgE antibodies in response to allergen exposure

Question 13

What are some predispositions for allergens?

Answer 13

Being male, small families, prenatal and smoking lastly genes on chromosome 5 and 11

Question 14

What enviornmental deteriminants might make you more prone to allergens?

Answer 14

• excessive hygeine
• recieveing antibiotics and vaccinations as a child
• decreased exposure to farm antigen
• having fewer siblings
• presence of pollutants

Question 15

What triggering events might make you more prone to allergens?

Answer 15

• flare ups of chronic illness
• acute pathogen exposure
• emotional stress
• hormone fluctuation
• nutritional deficits
• exposure to pollutants