Allergies Flashcards
What is an allergy?
An adverse health effect that is due to a specific immune response and occurs reproducibly upon exposure to the culprit antigen
What two key features make a reaction an allergy?
Involvement of the immune system
Symptoms to occur with each exposure
What is atopy?
A personal/familial tendency to produce IgE antibodies in response to ordinary exposures to potential allergens usually proteins.
Strong association with asthma, rhinitis and conjunctivitis
Describe Type 1 hypersensitivity reaction
IgE
Within 1 hr
Allergic rhinitis, asthma, systemic anaphylaxis
Describe type 2 hypersensitivity reactions
IgG/IgM
Hours to days
Haemolytic anaemia
Describe type 3 hypersensitivity reactions
Immune complex mediated
1-3 weeks
Serious sickness, SLE
Describe type 4 hypersensitivity reactions
T-cell mediated
Days to weeks
Rash
SJS
What is anaphylaxis?
An allergic or hypersensitivity reaction that is rapid, severe and life threatening
What are the symptom of anaphylaxis?
Skin: urticaria, oedema, flushing
Resp symptoms: cough, wheeze stridor
GI symptoms: vomiting, diarrhoea, crampy painful
CVS symptoms: tachycardia hypotension, dizziness, shock
Who should be carrying an adrenaline auto-injector (AAI)?
Allergy to high risk foods (peanuts, tree nuts, seeds, fish and shellfish)
Previous anaphylaxis
Idiopathic anaphylaxis
Unstable or moderate to severe persistent asthma with food allergy
What are some important questions to ask when a child presents with an allergic reaction?
Ingredients of food (if consumed something)?
Was it the first time exposure?
Immediate versus delayed reaction?
Was child well that day?
(If younger) was baby breast fed or bottle fed?
Other symptoms?
