Food Allergies

For many of us, food plays a big part of life. But for some people, eating particular foods can result in severe and sometimes life-threatening consequences. A food allergy is caused when the immune system reacts to a normally harmless food or substance in food (allergen), wrongly identifying it as danger. This triggers a protective response in the body, resulting in the production of allergy antibodies (proteins in the immune system) which identify and react to foreign substances.

An allergic reaction can result in a range of different symptoms varying in severity, which can occur anywhere between minutes to hours after exposure. This is different to food intolerance which is a chemical reaction resulting in mild symptoms. Food allergies are becoming increasingly common, affecting roughly 10% of infants and 2% of adults in Australia. Untreated food allergies can be extremely dangerous, so early detection and diagnosis by a professional is important in learning how to manage the condition, and what to do if an allergic reaction occurs.

Allergy or Intolerance

Food intolerance and allergies are often confused, as some symptoms can be similar - however a food intolerance is a chemical reaction, not allergic. A food intolerance does not involve the immune system, doesn’t result in severe allergic reactions, and won’t show on allergy testing. Intolerance to a food or preservatives found within food and drink, can result in a bodily response such as wheezing, asthma, hay fever, and hives.

Adverse reactions from food could also be an indication of something else, such as food poisoning, toxicity, enzyme deficiencies, food aversion, or skin contact irritation with certain foods. If you believe you have a food allergy or intolerance, it is best to speak with your GP to have this correctly diagnosed.

Food allergy symptoms

For people with food allergies, exposure to even a small amount of the problem food can cause an allergic reaction, and in some cases can be life threatening. Allergic reactions often affect the facial area, gastrointestinal tract, skin, cardiovascular system and respiratory tract, and can vary in severity between each person, and even each exposure. Symptoms often surface in one or multiple ways on the body.

Mild to moderate symptoms:

  • Itching, burning or swelling of/around the mouth and lips

  • Swelling of face or eyes

  • Abdominal pain

  • Nausea and vomiting

  • Skin rash (eczema) or hives

  • Diarrhoea and/or stomach cramps

Symptoms of a severe allergic reaction and/or anaphylaxis:

  • Swelling of the tongue

  • Swelling and tightness of the throat

  • Difficulty talking and swallowing

  • Breathing difficulties; coughing, wheezing and asthma

  • Weak pulse

  • Pale and limp (in children)

  • Dizziness or fainting

  • Heart palpitations

  • Shock or circulatory collapse

  • Anaphylaxis; potentially life threatening

Some food allergies are harder to identify. Particularly in young children, other symptoms such as reflux, colic or chronic diarrhoea may not be immediately connected to being a food allergy, but is something to be aware of.

Anaphylaxis is the most severe form of allergic reaction, and can be deadly. Often involving multiple body systems (gastrointestinal tract, respiratory, skin and cardiovascular), anaphylaxis can occur within minutes of exposure to the trigger food and become rapidly life threatening. Deaths from anaphylaxis are rare, and most cases can be prevented by avoiding triggers and always carrying appropriate aid to administer (e.g. adrenaline). Anaphylaxis must always be treated as a medical emergency, and requires urgent medical attention.

Areas of the body affected by food allergy

  • Eyes

  • Nose

  • Mouth

  • Throat

  • Swelling

  • Digestive system

  • Skin

  • Lungs

  • Central nervous system

Allergic reaction severity

Food allergies can range in severity, and may be influenced by many factors:

  • Severity of allergy

  • Amount of food consumed

  • Eaten whole or mixed with other food (e.g. a whole egg v a muffin containing egg)

  • Form of food – liquid may be absorbed faster, and cooked food may be better tolerated

  • Exercise close to meal can worsen severity

  • Alcohol intake

  • Asthma – presence or absence of

  • Menstrual cycle

Main causes of food allergies

Exposure (eating, drinking, or inhaling) to allergens in certain foods can trigger an allergic reaction, ranging from mild to very severe. While any food can cause an adverse reaction, eight core food types account for 90% of reactions:

  • Eggs

  • Milk or dairy

  • Peanuts

  • Tree nuts (e.g. brazil nuts, almonds, cashews, walnuts, pine nuts)

  • Fish

  • Shellfish

  • Wheat

  • Soy

Certain seeds (sesame and mustard) are also common food allergy triggers and considered a major allergen in some countries. People who are allergic to a particular food may also be allergic to related foods (e.g. someone allergic to prawns may also react to crab and lobster), so it’s best to approach related foods with caution.

Can food allergies go away?

Food allergies in children can be outgrown, particularly those allergic to cow’s milk, soy, wheat or egg. However, if an allergy develops for the first time in an adult, it is more likely to persist.

Diagnosing Food Allergies

If you notice a reaction or symptoms appearing each time you consume a particular food, you may have a food allergy. As the symptoms of food allergy vary in each person, and can change in severity each time, it can be complicated to diagnose. It is essential to have this diagnosed by a GP, clinical immunologist or allergy specialist who can decide which food allergy tests to perform, determine if an allergy exists, and support you in managing your food allergy once a diagnosis is made. Self-diagnosis or ignorance of a potential food allergy is strongly discouraged - not only is it uncomfortable and prolonging the inevitable, but could prove dangerous.

Allergy tests

In making a diagnosis, allergists or GPs will often ask detailed questions about your history of allergy symptoms. Skin prick and blood tests may be used to indicate whether food-specific IgE antibodies are present in your body. In some cases, an oral food challenge (or temporary elimination diet) may also be used to help identify allergens, however these should be conducted under close medical supervision.

Managing and Treating Food Allergies

Once a food allergy is diagnosed, the most effective treatment is to avoid the trigger food. However even when people are very careful to avoid certain foods, exposure can happen every now and then. People with food allergies can learn to manage their condition with the support of a clinical immunology/allergy specialist, and preparation measures:

  • Carry an adrenaline autoinjector (EpiPen) and ASCIA Action Plan at all times

  • Know the signs and symptoms of an allergic reaction, and what to do if it occurs

  • Read and understand food labels

  • Communicate the allergy clearly with wait staff when eating out

  • Communicate with school staff and teachers for children with allergies

  • Be aware of cross-contamination of food allergens when preparing food

  • Check medication – ask your pharmacist to check any medication you take doesn’t contain an allergen (ie. lactose)

ASCIA Action Plan

People with an allergy should have an ASCIA (Australasian Society of Clinical Immunology and Allergy Action Plan for Anaphylaxis and an adrenaline (epinephrine) autoinjector always on-hand, if prescribed by your GP.

What to do if an allergic reaction occurs

For severe reactions, or any signs or symptoms of anaphylaxis, treat it as a medical emergency and seek help immediately. If a mild allergic reaction occurs, there a number of measures you can take to help manage the situation:

  • Stop eating the food immediately

  • OTC (over-the-counter) antihistamines may help reduce symptoms of a mild reaction

Most people who experience food allergies can learn to live with the condition through reliable diagnosis, careful management of it, and the right support. Your local MediADVICE is here to assist with expert advice on any allergy concerns you have, and what products may be right for you. Speak to us today.

General advice only – this information should not replace the information provided to you by your health care professional. If symptoms are severe or persist, please speak to your health care professional. Information current as of date of publishing.

Sources:

1: https://www.allergy.org.au/patients/food-allergy/food-allergy

2: https://www.healthline.com/nutrition/common-food-allergies#section1

3: https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/food-allergy-and-intolerance

4: https://acaai.org/allergies/types/food-allergy

5: https://allergyfacts.org.au/allergy-anaphylaxis/what-is-anaphylaxis