Food allergy is an allergic response to particular foods or food additives.
Eating or drinking an allergenic substance is the common cause of allergic reaction. In some highly sensitive people however, skin contact with or inhalation of allergens may cause severe symptoms.
Studies show that about 6 per cent of children and 1 - 2 per cent of adults have a food allergy. Babies and young children are most often allergic to milk, eggs, wheat, soyabean products and peanuts. Older children and adults are most often allergic to peanuts, tree nuts (walnuts, almonds and cashews), fish and shellfish. Allergies to food dyes and colours are rare.
Food allergy vs food intolerance
Many food intolerances are mistaken for allergies. A food intolerance is an adverse food-induced reaction that does not involve the immune system. Sugars and fats do not produce an allergic response. Lactose intolerance is due to difficulty digesting the sugar in milk and is also not an allergy. Food allergies do not cause hyperactivity.
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With no cure for food allergies, the best defence is prevention and careful allergy management. Outlined below are some tips to help in the prevention of an allergic reaction.
- You may need to send allergic children to parties with their own special party food.
- Warn relatives, baby-sitters, teachers and other caregivers about the problem.
- Take extra care with babies and young children. Ensure a child with a food allergy understands rules about not sharing food. Remember to tell anybody caring for the child about their allergy. Give strict instructions and supplies of allowed foods. Also give all treatment details/emergency numbers, etc.
- Carefully read the content labels of foods in supermarkets. For example, the terms 'whey' or 'casein' indicate the presence of dairy products.
- Plan ahead - write a list of foods you can tolerate and ask your dietitian about special dietary alternatives/recipes.
- If you are eating out, contact the host/chef in advance and explain your dietary needs. Offer to supply your own food or see if the menu can be adapted for you. Always make a point of discussing beforehand so you are never tempted to eat anything you shouldn't!
- Carry your own appropriate snack food with you.
- Make sure you drink at least 2 litres of water each day.
- Keep a food and symptom diary so that if you have a reaction, you can pinpoint what may have triggered your symptoms.
- Contact your local supermarket customer services; ask for advice on 'free-from' foods.
- Freeze a selection of safe meals, so that you always have something to eat on hand.
- Make everyone aware if you have a life-threatening allergy. Consider wearing allergy identification jewellery, and always carry your medication with you. Make sure you have enough to last through holiday periods, etc.
- If you are travelling overseas, obtain some allergy translating cards in the language of your destination. Always find out where the nearest hospital/doctor is in case of an emergency.
- Join a support group. Ask your doctor for advice or contact the organisation listed in this topic. A support group can be a great source of information, literature, research and recipes.
- Contact your doctor if you are at all concerned or if your symptoms change in any way.
- Make sure you and whoever prepares your food are aware of cross-contamination issues. Always prepare your food in separate clean areas and avoid communal areas such as buffet bars where contamination may occur.
- Always be aware of hidden allergens. Never try something without checking the ingredients list first.
Food allergy occurs when the body's immune system over-reacts to usually harmless substances (called allergens) in some foods. Hay fever, eczema and many cases of asthma are all caused by allergies. When an allergic person comes into contact with an allergen, their immune system produces a special kind of antibody (IgE). Other cells release further chemicals such as histamine that cause the symptoms of an allergic reaction.
While allergies are not directly inherited, you may inherit a tendency to allergy, called atopy. This is called being atopic. A child with no history of allergies in the family has a 10 per cent chance of developing hay fever, food allergies, eczema or asthma. A child with one parent with allergies has a 30 per cent chance, while a child with two atopic parents has a 60 per cent. Allergies start only if you are then exposed to an allergen.
Signs and Symptoms
Symptoms vary between individuals. Symptoms typically appear within minutes to two hours after the person has eaten the food to which they are allergic. The most common symptoms include:
- Tingling sensation in the mouth
- Swelling of the tongue and the throat
- Difficulty swallowing and/or breathing
- Nasal congestion
- Runny or itchy nose (rhinitis)
- Hives or skin rash
- Abdominal cramps
- Wheezing (this often sounds like the wheezing associated with asthma)
- In severe cases, drop in blood pressure, loss of consciousness and respiratory failure.
Food allergies can only be correctly diagnosed by a doctor. There is no cure for food allergies. Treatment is aimed at identifying and avoiding the trigger foods. Always check food labels carefully and do not eat anything which is unlabelled.
- Your pharmacist may suggest antihistamines. Ask about any possible side effects, (eg. drowsiness).
- If the allergy has caused a rash, your pharmacist may recommend an anti-inflammatory cream, such as hydrocortisone cream.
Allergy testing, to identify the cause of a particular allergy, can be done any time from four months of age to adulthood. Different tests are used to identify the allergen. These include; the skin prick test, a blood test known as the Radioallergosorbent Test (RAST) and the allergen patch test. Your Doctor will recommend the most suitable type of test for you.
In case of a severe reaction (anaphylactic shock), medical attention must be sought immediately as it could be life threatening'
- Dial for an ambulance and tell them the patient is having an allergic reaction.
- If the person has an injectable dose of adrenaline and you know how to use it, administer the dose to the patient.
- Loosen clothing around the neck and chest.
- If able to swallow, give oral antihistamine (in tablet form).
- Observe the airway, breathing and circulation.
- If breathing stops, commence CPR.
Your doctor may recommend you carry an injectable dose of adrenaline with you at all times. Adrenaline is used in severe reactions and can be a life-saving measure.
- It's essential to identify allergenic foods so other more serious problems do not arise. Ask your doctor for a referral to an allergy specialist.
- Foods that are most commonly associated with allergic reactions include; peanuts, cow's milk, soya, seafood and eggs. Similar reactions can occur to some chemicals and food additives.
- Fortunately, the majority of food allergies are not severe, and will disappear with time, particularly in children. Allergies to nuts, seeds and seafood, however, tend to persist throughout life.
- In some cases a temporary 'elimination diet' under close medical supervision will be needed. Potentially allergic foods are eliminated from the diet then reintroduced to help identify the cause of the allergic reaction.
A person who has a food allergy should ALWAYS seek the advice of an allergy specialist before taking any nutritional supplements as they main contain allergy-triggering ingredients. Supplements may be of benefit in reducing symptoms, but are not a cure for allergies.
- Garlic and onion may reduce the severity of a skin reaction.
- Bromelain (an enzyme found in pineapple) is thought to inhibit inflammation and may assist in reducing the inflammatory response triggered by allergy.
- Vitamin C reduces histamine release and the sensitivity of inflammatory cells in responding to allergens.
- Albizzia may be used for its 'anti-allergy' properties. It is believed to help with lowering allergy producing antibodies and reducing inflammation.
- Evening primrose oil has proven anti-inflammatory properties which, if taken over a period of time, may help to reduce the severity of allergies.
Organisations & Support Groups
21 Robinson Close
Hornsby Heights NSW 2077
Ph: 1300 728 000
World Allergy Organization
555 East Wells Street
Milwaukee, WI 53202-3823
Phone: +1 414 276 1791
Fax: +1 414 276 3349
Ask your Pharmacist for advice.
- Try to identify the source of the problem and make every effort to avoid any known allergens.
- Follow the Diet Hints. Try to identify any possible food allergies with a Doctor or Dietitian.
- Your Pharmacist may suggest an antihistamine. There are several brands available. Watch for any possible side effects which may include drowsiness. New products are on the market which have fewer side effects.
- If the allergy has caused a rash, your Pharmacist may recommend an anti-inflammatory cream.
- Vitamin C is considered by some people to have natural antihistamine properties.
- Your Pharmacist can teach you how and when to use your adrenaline injector (if your Doctor has recommended one).