Food allergy Flashcards
What is meant by a food allergy?
Food allergy describes when symptoms are caused by an immune reaction, usually IgE mediated, but sometimes non-IgE (thought to be T-cell mediated but not well understood)
What are some childhood allergies that children tend to grow out of?
Milk, eggs, soya and wheat
What are some common food allergens?
- Cow’s milk
- Chicken eggs
- Fish
- Shellfish (Esp. prawns)
- Soya
- Peanuts
- Tree nuts
- Wheat
These are up 90% of all food allergies
What are tree nuts?
Tree nuts are any nuts that grow on a tree, including hazelnuts, almonds, walnuts, Brazil nuts, cashews and pistachio nuts
Are peanuts classed as tree nuts?
No, they grow underground
What are some foods that contain soya?
Processed meats
Margarine
Ice cream
Vegetarian meat substitutes
Baked goods
What are the 2 main mechanisms of symptoms in cow’s milk allergy?
IgE mediated
Non-IgE mediated
What are some IgE mediated symptoms of cow’s milk allergy?
Pruritus
Erythema
Acute urticaria
Acute angioedema
GI symptoms
Respiratory symptoms
Anaphylaxis
What are some non-IgE mediated symptoms of cow’s milk allergy?
Pruritus
Erythema
Atopic eczema
GI symptoms
Respiratory symptoms
Anaphylaxis
How should cow’s milk allergy be managed?
Follow a cow’s milk free diet until 9-12 months of age and for at least six months
What is the main alternative to cow’s milk in cow’s milk allergy?
Extensively hydrolysed formula milk
Why is soya milk not recommended as an alternative to cow’s milk?
These children also tend to have an increased risk of soya allergy, and it may also interfere with the absorption of minerals and trace elements
Why is other mammalian milk not recommended as an alternative to cow’s milk in cow’s milk allergy?
Children with CMA will also react to these
What is meant by extensively hydrolysed formula milk?
A formula containing cow’s milk proteins that have been broken down into very short
chains and therefore do not trigger an allergic reaction
What is a possible option in severe cow’s milk allergy?
Amino acid based formula
What are some examples of extensively hydrolysed formula?
- Althera - Birth onwards
- Aptamil Pepti 1 - Birth onwards
- Aptamil Pepti 2 - >6months of age
- Nutrimigen 1 with LGG - Birth onwards
- Nutramigen 2 with LGG - >6months of age
- Similac Alimentum - Birth onwards
Why are rice milks not used in children under 5?
There is an increased arsenic content
What are some IgE-mediated effects of food allergy on the GI system?
- Angioedema (Lips, tongue, palate)
- Oral pruritus
- Nausea
- Colicky abdominal pain
- Vomiting
- Diarrhoea
What are some non-IgE mediated effects of food allergy on the GI tract?
- GORD
- Loose or frequent stools
- Infantile colic
- Food refusal
- Constipation
- Perianal redness
- Pallor or tiredness
- Faltering growth
What are some upper respiratory tract symptoms of food allergy?
- Nasal itching
- Sneezing
- Rhinorrhoea
- Congestion
What are some lower respiratory tract symptoms of food allergy?
- Cough
- Chest tightness
- Wheezing
- Shortness of breath
What are some important points in a good allergy focussed history?
- Personal history of atopy
- Family history of atopy
- Trigger foods
- Cultural and religious factors
- Feeding history
- Response to elimination
What are some tests that can aid diagnosis in food allergy?
- Specific IgE blood testing
- Skin prick testing
- Food challenge test
What are the 3 stages of acute food allergy management?
- Give chlorphenamine dose appropriate to weight (Give inhaler if asthmatic and wheezy)
- If not resolving within 30 minutes, give prednisolone dose relative to weight and call for help
- If becomes blue or collapses, give IM adrenaline and call 999
