food allergy and resp allergy Flashcards
Can you develop an allergy against lactose?
No! Only against proteins! Lactose is a sugar!
Which allergies persist to adulthood vs go?
Milk and effs - go
peanuts, wheat, nuts, shellfish, fish persist to adulthood
Should an atopic mother avoid peanuts in preg?
No
Early age exposure from 4 months and older ok
Gold standard for IgE mediated food allergy?
Food challenge
When is tryptase high?
1-4 hours post anaphylaxis but VERY UNCOMMON with food anaphylaxis
React to peanuts, likely to react to…
lentils, peas, legumes
10% also soy allergy
treenuts
sesame often
note NOT cross reacting but tend to group allergies.
If someone has exercise induced anaphylaxis, what should you check?
Find out the underlying food acting as cofactor and avoid 4-6 hours pre exercise
test recombinant omega-5-gliadin IgE
Factors that increase risk death in anaphylaxis?
asthma delayed adrenaline eating away from home and allergic food 40-50s and insect or drug allergy teenagers and food allergy
How does Omalizumab work?
binds Fc portion of IgE , prevents from binding to mast cells and back on to dendritic cells
Can use in asthma where there is INCREASED TOTAL IgE, sensitised to perennial aerosols, frequent exac, high dose inhaled steroids.
management of allergic rhinitis
avoidance
antihistamines and IN steroids
desensitisation subling or subcut
Egg allergy strong assoc with….
atopic dermatitis
Skin prick for food allergy testing?
Yes but NEVER intraderma- much higher risk of severe reaction
Insect sting allergy- do you do intradermal testing?
Yes, both skin prick and intraderma testing done here
Note POOR CORRELATION with insects between size of positive skin test, IgE level and severity of allergy
Cannot desesnitise someone to an insect thing if just a large local reaction. Cutaneous systemic reaction and anaphylaxis can have immunotherapy
Cannot re-check IgE or skin prick post desens- not useful
Does tryptase help tell between IgE mediated and non IgE mediated causes of mast cell degranulation?
No
Can you do desens to med for type 2-4? SJS/TEN? haemolytic anaemia? interstitial nephritis?
No
Does pen/ceph cross reactivity relate to generation of cephalosporin?
Earlier- more cross reactivity
Later- less so
Sulphonamide reaction in HIV vs non HIV?
more common ++ in HIV positive
often delayed 7-10 days; fever, pruruitis
Most common NMDA to cause anaphylaxis?
succinylcholine
good sens on skin prick testing
latex what type of hypersens?
Type 1 and 4
can do SPT or specific IgE or challenge
Does seafood allergy increase risk of contrast allergy?
No - it is a contrast allergy to the protein of the seafood not the iodine
Can do SPT for immediate type - but low sens
Cannot do IgE
Can do patch testing for delayed type
How to investigate chlorhex reaction?
IgE sens and specific
SPT sens and spec good
Mechanism for ACE angioedema
Bradykinin usually broken down by ACE into inactive metabolites. Instead shunted in to BK2R–>NO and increase vasc permeability
NO correlation with cough
NOT IgE mediated
NSAID allergy is mediated by?
When block COX 1 and 2, the arachidonic acid is shunted from the prostaglandin pathway to the lipoxygenase pathway–>lots of leukotrienes
Clopidogrel no cross reactivity if properly aspirin allergic
Diagnose by challenging with COX1 and if pos then COX2
Desensitisation only good for NON anaphylaxis
Is there immunotherapy for food allergy?
No
