If you didn’t have food allergies as a toddler, is it possible to develop them as an adult? The short answer is yes. But the the explanation why are way more complicated.
Preschoolers are about 4 times more more likely to have a food allergy than adults and usually tend to grow out of it as they become old.
It’s hard to get accurate figures on adult food allergy prevalence. The Australian National Allergy Council reports one in 50 adults have food allergies. But a US survey suggested as many as one in ten adults were allergic to a minimum of one food, with some developing allergies in maturity.
What is a food allergy
Food allergies are immune reactions involving immunoglobulin E (IgE) – an antibody that’s central to triggering allergic responses. These are referred to as “IgE-mediated food allergies”.
Food allergy symptoms which might be not mediated by IgE are frequently delayed reactions and called food intolerances or hypersensitivity.
Food allergy symptoms can include hives, swelling, difficulty swallowing, vomiting, throat or chest tightening, trouble respiratory, chest pain, rapid heart rate, dizziness, low blood pressure or anaphylaxis.
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IgE-mediated food allergies will be life threatening, so all adults need an motion management plan developed in consultation with their medical team.
Here are 4 IgE-mediated food allergies that may occur in adults – from relatively common ones to rare allergies you’ve probably never heard of.
1. Single food allergies
The most common IgE-mediated food allergies in adults in a US survey were to:
- shellfish (2.9%)
- cow’s milk (1.9%)
- peanut (1.8%)
- tree nuts (1.2%)
- fin fish (0.9%) like barramundi, snapper, salmon, cod and perch.
In these adults, about 45% reported reacting to multiple foods.
This compares to commonest childhood food allergies: cow’s milk, egg, peanut and soy.
Overall, adult food allergy prevalence appears to be increasing. Compared to older surveys published in 2003 and 2004peanut allergy prevalence has increased about three-fold (from 0.6%), while tree nuts and fin fish roughly doubled (from 0.5% each), with shellfish similar (2.5%).
While latest adult-onset food allergies are increasingchildhood-onset food allergies are also more more likely to be retained into maturity. Possible reasons for each include low vitamin D status, lack of immune system challenges as a consequence of being overly “clean”, heightened sensitisation as a consequence of allergen avoidance, and more frequent antibiotic use.
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2. Tick-meat allergy
Tick-meat allergy, also called α-Gal syndrome or mammalian meat allergy, is an allergic response to galactose-alpha-1,3-galactose, or α-Gal for brief.
Australian immunologists first reported links between α-Gal syndrome and tick bites in 2009, with cases also reported within the United States, Japan, Europe and South Africa. The US Centers for Disease Control estimates about 450,000 Americans might be affected.
The α-Gal accommodates a carbohydrate molecule that’s certain to a protein molecule in mammals.
The IgE-mediated allergy is triggered after repeated bites from ticks or chigger mites which have bitten those mammals. When tick saliva crosses into your body through the bite, antibodies to α-Gal are produced.
When you subsequently eat foods that contain α-Gal, the allergy is triggered.
These triggering foods include meat (lamb, beef, pork, rabbit, kangaroo), dairy products (yoghurt, cheese, ice-cream, cream), animal-origin gelatin added to gummy foods (jelly, lollies, marshmallow), prescription medications and over-the counter supplements containing gelatin (some antibiotics, vitamins and other supplements).
Tick-meat allergy reactions will be hard to recognise because they’re normally delayed, and so they will be severe and include anaphylaxis. Allergy organisations produce management guidelinesso all the time discuss management together with your doctor.
3. Fruit-pollen allergy
Fruit-pollen allergy, called pollen food allergy syndrome, is an IgE-mediated allergic response.
In susceptible adults, pollen within the air provokes the production of IgE antibodies to antigens within the pollen, but these antigens are just like ones present in some fruits, vegetables and herbs. The problem is that eating those plants triggers an allergic response.
The most allergenic tree pollens are from birch, cypress, Japanese cedar, latexgrass, and ragweed. Their pollen can cross-react with fruit and vegetablesincluding kiwi, banana, mango, avocado, grapes, celery, carrot and potato, and a few herbs corresponding to caraway, coriander, fennel, pepper and paprika.
Fruit-pollen allergy just isn’t common. Prevalence estimates are between 0.03% and eight% depending on the country, but it will probably be life-threatening. Reactions range from itching or tingling of lips, mouth, tongue and throat, called oral allergy syndrometo mild hivesto anaphylaxis.
4. Food-dependent, exercise-induced food allergy
During heavy exercise, the stomach produces less acid than usual and gut permeability increases, meaning that small molecules in your gut usually tend to escape across the membrane into your blood. These include food molecules that trigger an IgE response.
If the person already has IgE antibodies to the foods eaten before exercise, then the chance of triggering food allergy reactions is increased. This allergy known as food-dependent exercise-induced allergywith symptoms starting from hives and swelling, to difficulty respiratory and anaphylaxis.
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Common trigger foods include wheat, seafood, meat, poultry, egg, milk, nuts, grapes, celery and other foods, which might have been eaten many hours before exercising.
To complicate things even further, allergic reactions can occur at lower levels of trigger-food exposure, and be more severe if the person is concurrently taking non-steroidal inflammatory medications like aspirin, drinking alcohol or is sleep-deprived.
Food-dependent exercise-induced allergy is amazingly rare. Surveys have estimated prevalence as between one to 17 cases per 1,000 people worldwide with the best prevalence between the teenage years to age 35. Those affected often produce other allergic conditions corresponding to hay fever, asthma, allergic conjunctivitis and dermatitis.
Allergies are a growing burden
The burden on physical health, psychological health and health costs as a consequence of food allergy is increasing. In the US, this financial burden was estimated as $24 billion per 12 months.
Adult food allergy must be taken seriously and people with severe symptoms should wear a medical information bracelet or chain and carry an adrenaline auto-injector pen. Concerningly, surveys suggest only about one in 4 adults with food allergy have an adrenaline pen.
If you may have an IgE-mediated food allergy, discuss your management plan together with your doctor. You may find more information at Allergy and Anaphylaxis Australia.
