Food allergy Flashcards
Food allergy is an adverse immune response to a food, commonly associated with (?) and (?) reactions, and less frequently associated with respiratory reactions and anaphylaxis
Cutaneous
GI
Food allergy is an adverse immune response to a food, commonly associated with cutaneous and GI reactions, and less frequently associated with (?) reactions and (?)
Respiratory
Anaphylaxis
What is the difference between a food allergy and food intolerance?
Food allergy is an immune response.
Food intolerance is non-immunological
What are the most common food allergens?
Cow's milk Hen's eggs Soy Wheat Peanuts Tree nuts Fish Shellfish
Why may a person with an allergy to cow’s milk also have an allergy to other mammalian milk?
Cross reactivity between similar foods
How do you manage a food allergy?
Strict avoidance of the food.
Educating patients about appropriate nutrition, food preparation, and the risks of accidental exposure is recommended, such as food and drinks to avoid, ensuring adequate nutritional intake, and interpreting food labels.
What drug is licensed to be used as an adjunct to dietary avoidance in patients with food allergies?
Sodium cromoglicate
- Oral, taken before meals (30-60 mins)
Acts by inhibiting the release of histamine and various membrane derived mediators from the mast cell
What education do patients with food allergies require? (6)
- Appropriate nutrition
- Food preparation
- The risks of accidental exposure (such as food and drinks to avoid)
- Ensuring adequate nutritional intake
- Interpreting food labels
- Training to use self-injectable adrenaline/epinephrine (if at risk of anaphylaxis)
Is there high or low quality evidence to support the use of antihistamines to treat acute, non-life threatening symptoms (such as flushing and urticaria) if accidental ingestion of allergenic food?
Low
Chlorphenamine maleate is licensed for the symptomatic control of food allergy.
Which drug is licensed for symptomatic control of food allergy?
Chlorphenamine maleate
- an antihistamine
- Oral: 4 mg every 4-6 hours; maximum 24 mg per day
- IM or IV: 10 mg, repeated if necessary; max 4 doses per day
What is first-line immediate treatment of food-induced anaphylaxis?
IM adrenaline/epinephrine
- ADULT: 500 micrograms, using 1 in 1000 (1 mg/mL) injection, repeat dose after 5 minutes if no response
Adrenaline/epinephrine acts on both (?) and (?) receptors
alpha
beta
What are the effects of adrenaline/epinephrine?
- Beta1 effects (2)
- Beta2 effect (1)
- Alpha effect (1)
Beta1 effects:
- increases heart rate
- increases contractility
Beta2 effect:
- peripheral vasodilation
Alpha effect:
- peripheral vasoconstriction
Acts on both alpha and beta receptors and increases both heart rate and contractility (beta1 effects); it can cause peripheral vasodilation (a beta2 effect) or vasoconstriction (an alpha effect).
What is the adult dose of IM adrenaline/epinephrine for emergency treatment of acute anaphylaxis?
500 micrograms, using adrenaline 1 in 1000 (1 mg/mL) injection, repeat dose after 5 minutes if no response
(further doses can be given if life-threatening features persist)
What is the child up to 6 months dose of IM adrenaline/epinephrine for emergency treatment of acute anaphylaxis?
100-150 micrograms, using adrenaline 1 in 1000 (1 mg/mL) injection, repeat dose after 5 minutes if no response
(further doses can be given if life-threatening features persist)