Allergy Flashcards
What is hypersensitivity?
An immune response that causes collateral damage to the self
How many types of hypersensitivity are there?
4
How fast is type 1 allergy?
Immediate
Minutes to 2 hours
Is type 1 allergy consistent with every exposure?
Yes
What are some routes of exposure to allergens?
Skin contact
Inhalation
Ingestion
Injection
What is the pathophysiology of Type 1 allergy
Allergen is encounteres
Dendritic cell takes up antigen
Presents antigen to T cell
TH2 cell releases IL4,5 and 13
Which activates B cells to release allergen specific IgE
Which activated mast cells causing them to degranulate
Releasing histamines, leukotrines, cytokines and prostaglandins
What is urticaria?
Extremely itchy compressible dermal swelling
When does urticaria appear?
Within 1 hour
How long does urticaria last?
2-6 hours
What does urticaria look like?
Hives
Nettle rash
What is angioedema/
Localised swelling of subcutaneous tissue
Non pitting
Not itchy
What are the symptoms of anaphylaxis?
Hives Flushing Facial swelling Rapid breathing Hypotension
What are some investigations for Type 1 allergy?
History
Specific IgE
Skin prick test
Challenge test
What is the treatment for type 1 allergy?
Allergen avoidance
Anti-histamine
Corticosteroids
Adrenaline auto-injector
What are the characteristics of a Type 4 allergy?
Delayed
Antigen specific
T cell mediated
Onset after 24-48 hours