Brayden is a 3 year old boy who has been referred to your clinic following one occasion where he developed some facial swelling and wheeze after ingesting peanuts. Not all food allergies present as classically as Brayden’s reaction to peanuts. In this post, we look at other types of food allergies.
This is known as pollen food syndrome.
It occurs predominantly in pollen-sensitised individuals, and severity may worsen during pollen season.
There is IgE mediated cross-reactive responses to allergens present in pollen and other plants.
It presents with an itchy mouth/throat with eating uncooked fresh fruits, vegetables, spices, sometimes nuts, latex. There is mouth/laryngeal swelling.
Oral allergy syndrome can result in anaphylaxis but this is uncommon.
Management of oral allergy syndrome depends on the food type.
Nuts – avoid, even if cooked as they usually still causes symptoms. Roasting peanuts/treenuts can enhance symptoms.
Fruits/veg – cooking, baking (even briefly microwaving) raw fruits/veg helps.
If patients can tolerate the cooked form, then they can continue to take them regularly.
Dietician input is helpful if there is severe dietary restrictions, as patients may need nutritional supplements.
There is conflicting evidence for inhaled allergen immunotherapy, and it is not currently recommended.
Eczema itself is cell-mediated. The early onset of eczema (<3 months of age) and severe eczema, make co-existent food allergy more likely.
Food allergy may aggravate pre-existent eczema in some individuals, but is not the cause. Most cases are IgE-mediated.
There can be acute flares of eczema after ingestion of food – subtle symptoms if passive transfer through breastmilk. Patients have positive food allergy tests.
Less commonly, cases are non IgE-mediated. Here, the onset of symptoms is delayed (6-48 hours). Patients have negative food allergy tests.
Most common non-IgE triggers are dairy, wheat and soy.
Treatment for both IgE and non-IgE mediated is an elimination trial and rechallenge in 1-2 weeks (via maternal diet if breastfed).
Food protein induced enteropathy (non-IgE)
- Occurs in early infancy (<3 years)
- Protracted diarrhoea, vomiting, abdo distension, failure to thrive, oedema
- Usually to cow’s milk, soy, or wheat
- If breastfed, there should be maternal dietary exclusion of the suspected food
- If formula fed – extensively hydrolysed formula, or amino acid formula if eHF is not tolerated
Food protein induced proctocolitis (non-IgE)
- Occurs in the first weeks to months of life (<3 months)
- Isolated, bloody stools, otherwise well and thriving
- Usually to cow’s milk, soy and 50% are breastfed
- Management is as per food protein induced enteropathy
Food protein induced enterocolitis (FPIES) (non-IgE)
- Occurs in young infants (4-6 months) at the onset of introduction to new foods
- Protracted diarrhoea, projectile vomiting, hypovolaemic shock
- Usually to cow’s milk, soy, rice, beef, poultry, grains
- In breastfed babies, there should be specialist review before any maternal dietary exclusion
- In bottle fed babies, management is as per food protein induced enteropathy
Eosinophilic oesophagitis (EoE) (mixed IgE/non-IgE)
- Can occur at any age
- GORD, post-prandial nausea, vomiting, food impaction, abdo pain, and diarrhoea
- Usually to cow’s milk, soy, wheat, egg, and sometimes to meat and grains
- In breastfed babies, there should be specialist review before any maternal dietary exclusion.
- In bottle fed babies, they can go onto an amino acid formula
One other to be aware of is food dependent exercise induced anaphylaxis.
Symptoms develop if exercise occurs within a few hours after eating. Occasionally it can occur when food is eaten post exercise. Patients develop extreme fatigue, warmth, flushing, pruritus, urticaria, and this progresses to anaphylaxis.
Patients should avoid food 4-6 hours before exercise.