Atopy Flashcards
Define atopy
genetic tendency to develop allergic diseases (eg. allergic rhinitis, asthma and atopic eczema)
Allergy risk factors (5)
first born
atopic parents
caesarean section delivery
bottle fed
early antibiotics
Role of Th1
biased towards fighting infections
involved in autoimmune diseases
Role of Th2
IgE production
mast cell activation
involved in allergic disease
Explain the dirt is good for you theory
no longer exposed to lots of different infections/bacteria due to improvements in sanitation/immunisation/hygiene
not enough stimulation of Th1 (infection fighting) side so we produce too many Th2 (allergy) cells
evidence = dirty upbringing (eg. farms) is protective for allergy
What is the atopic triad
asthma
atopic eczema
allergies
(+allergic rhinitis)
Symptoms of a food allergy
anaphylaxis
diarrhoea
abdominal pain
vomiting
failure to thrive
eczema
Which foods must be declared if included in foods (European Directives)?
milk
eggs
cereals containing gluten
peanuts
nuts
fish
soybeans
sesame
crustaceans
molluscs
celery
mustard
lupin
sulphur dioxide (at certain concentrations)
Describe cross reactions
allergy to one substance can increase the likelihood of having an allergy to another due to similar protein patterns that the body detect as similar and therefore mounts an allergic response
Give some examples of cross reactions
same group:
- peanuts + peas (legumes)
different group:
- egg + peanut
- milk + soya
- egg yolk + bird feathers
- kiwi/banana + latex
- pollen - fruit syndrome (birch common in UK)
What response would indicate a positive skin prick test?
weal >4mm
Example of an allergy emergency plan
avoidance
antihistamine ASAP
repeat antihistamine
adrenaline (epipen or anapen) - must be >15kg
seek medical help (adrenaline only works ~30mins)
