Allergy Flashcards
Which diagnostic test can be used post anaphylaxis to confirm it?
Mast cell tryptase
How are seasonal allergic rhinitis treated?
Nasal corticosteroids
Anti-histamines
How is insect allergy treated?
5 years of immunotherapy
How are symptoms related to location of exposure in non-anaphylaxis allergy?
Symptoms typically appear at the site of exposure
What are the mechanisms of the chronic allergic reaction?
Eosinophils release of basic proteins, leukotrienes
Continued release of mast cell histamine, lipids
Neuropeptides released from Th2 cells
How is adrenaline best administered in anaphylaxis?
0.5mg IM
Wait 5 minutes and give more if needed
After 3 administration considerd infusion
What is the gold standard of allergen testing?
Challenge testing
What is a non-sedative anti-histamine?
Cetirizine
When are challenge tests used?
Usually used when RAST and SPT negative/discordant and there is a good clinic story
What are the diagnostic tests for IgE allergy?
Skin prick test
Serology - CAP
Challenge test
Who should get subcutaneous injection immunotherapy?
Venom allergy
Allergic rhinitis
Mild, well controlled allergic asthma
Why do thunderstorms exascerbate allergies?
Storm break up pollen seeds allowing them to travel deeper into the lung
What is the dose of adrenaline for anaphylaxis in adults and children?
- 5mg in adults
- 01mg/kg
How does subcutaneous injection immunotherapy work?
Injecting allergen subcutaneously at increasing doses over longer time periods
Class switching the response to an allergen to IgG
What are the advantages and disadvantages of in vitro assays?
Adv
Highly available
Safe
Specific
Standardised and quantitative
Neg
- High false positive rate
- Medicare only subsizes 4 allergen at once
What is the new alternative to subcutaneous injection immunotherapy? What are the advantages?
Sublingual immunotherapy
Easier to administer
Less anaphylaxis risk
How can you treat allergies?
Subcutaneous allergen immunotherapy
What is the criteria for a positive skin prick test?
>3mm
Which age group is most likely to die from anaphylaxis?
16-24
What is the cardiovascular response in anaphylaxis?
Hypotension
What is the mechanism of anaphylaxis?
Massive mediator release from mast cell and basophils
Histamine causes vasodilation, fluid extravasation, bronchial smooth muscle contraction and mucosal oedema
What is the definition of anaphylaxis?
Generalised IgE-mediated response involving the cardiovascular and/or respiratory system
How can you treat anaphylaxis?
Avoiding trigger
Management of inadvertent exposure
What are some milder symptoms of anaphylaxis?
Pruritis
Vomiting, diarrhoea
Flashing, urticaria
What are the major sources of fatal anaphylaxis?
Medications 50%
Insects 25%
Food 20%
Define what an allergy is
An inappropriate or harmful immune response to foreign substances that are otherwise not harmful to the body, mediated largely, though not exclusively by immunoglobulin E (IgE)
What are the advantages and disadvantages of the skin prick test?
Adv - Highly sensative (99%)
- In vivo
- Fast results
Disadv - May lack sensitivity due to sensitized but asymptomatic patients
- Potential for anaphylaxis
How do you measure allergen specific IgE?
RAST (radio-allergosorbent test)
EAST
