A food allergy is an abnormal reaction to allergens in food by the body's immune system. If one parent is suffering from a food allergy, there is a 20-40% probability that the child will also suffer from it. The probability increases to 40-60% if both parents suffer from a food allergy. Foods that commonly cause allergies include seafood, milk, eggs, soy, wheat and nuts such as peanuts, cashews, walnuts and pecans.
What Are The Causes Of Food Allergies?
Food allergies happen when the body’s immune system regards a food as harmful, therefore releasing antibodies to fight the allergen.
What Are The Signs Or Symptoms?
Symptoms may be mild or severe. They usually start minutes after eating the food, but they can occur even a few hours later. For people with a severe allergy, symptoms can start within seconds.
Mild symptoms of this condition include:
- Congested nose.
- Tingling in the mouth.
- An itchy, red rash.
- Vomiting
- Diarrhoea
For people with a severe allergy, a life-threatening reaction called anaphylaxis can occur. Get help right away if you have symptoms of anaphylaxis, such as:
- Feeling warm in the face (flushed). This may include redness.
- Itchy, red, swollen areas of skin (hives).
- Swelling of the eyes, lips, face, mouth, tongue, or throat.
- Difficulty breathing, speaking, or swallowing.
- Noisy breathing (wheezing).
- Dizziness or light-headedness.
- Fainting
- Pain or cramping in the abdomen.
How Is Food Allergy Diagnosed?
This condition can be diagnosed based on:
- A physical exam.
- Your medical history.
- Skin tests.
- Blood tests.
- A food challenge test. This test involves eating the food that may be causing the allergic response while being monitored for a reaction by your healthcare provider.
- The results of an elimination diet. The elimination diet involves removing foods from your diet and then adding them back in, one at a time.
- A food diary. Taking notes of what you have eaten to determine the cause of your food allergy.
How Is Food Allergy Treated?
There is no cure for food allergies. Treatment focuses on preventing exposure to the food or foods you are allergic to and treating reactions if you are exposed to the food. Mild symptoms may not need treatment.
Severe reactions usually need to be treated at a hospital. Treatment may include:
- Medicines that help:
- Tighten your blood vessels (epinephrine).
- Relieve itching and hives (antihistamines).
- Widen the narrow and tight airways (bronchodilators).
- Reduce swelling (corticosteroids).
- Oxygen therapy to help you breathe.
- IV fluids to keep you hydrated.
After a severe reaction, you may be given rescue medicines, such as an epinephrine injection, commonly called an Epi-pen (pre-filled automatic epinephrine injection device). Your healthcare provider may teach you how to use it if you are accidentally exposed to an allergen.
Follow These Instructions At Home:
If you have a potential allergy:
- Follow the elimination diet as told by your healthcare provider.
- Keep a food diary as told by your health care provider. Every day, write down:
- What you have eaten and drank and when you consumed them.
- What symptoms you have and when the symptoms occurred.
If you have a severe allergy:
- Wear a medical alert bracelet or necklace that describes your type of food allergy. Eg: peanut allergy / dairy allergy.
- Carry your Epi-pen with you at all times. Use the Epi-pen as told by your health care provider.
- Make sure that you, your family members, and your employer know the signs of anaphylaxis and how to use an Epi-pen in the event that it is needed.
- If you think that you are having an anaphylactic reaction, use your Epi-pen.
- Replace your Epi-pen immediately after use, in case you have another reaction.
- Receive medical care after using your Epi-pen. This is important because you can have a delayed, life-threatening reaction after taking the medicine (rebound anaphylaxis).
General instructions
- Avoid the foods that you are allergic to.
- Read food labels before you eat packaged items. Look for ingredients that you are allergic to.
- When you are at a restaurant, tell your server that you have an allergy. If you are unsure whether a meal has an ingredient that you are allergic to, ask your server.
- Inform all healthcare providers that you have a food allergy.
- If you think that you might be allergic to other food substances, talk to your health care provider. Do not try consuming food to see if you are allergic to it without consulting your healthcare provider first.
Get Help Right Away If You Have Symptoms Of Anaphylaxis:
- Flushed skin.
- Hives
- Swelling of the eyes, lips, face, mouth, tongue, or throat.
- Difficulty breathing, speaking, or swallowing.
- Wheezing
- Dizziness or light-headedness.
- Fainting
- Pain or cramping in the abdomen.
These symptoms may represent a serious emergency problem. You should not wait to see if the symptoms will go away. Use your Epi-pen as instructed by your healthcare provider and get medical help right away by calling 999. It is also important that you do not drive yourself to the hospital.
If you needed to use an Epi-pen, it means that you need more medical care even if the medicine in the Epi-pen seems to be making your condition better. This is important because anaphylaxis may happen again within 72 hours.
Summary
- A food allergy is an abnormal reaction to a food (food allergen) by the body's defence system (immune system).
- There is no cure for food allergies. Treatment focuses on preventing exposure to the food or foods you are allergic to and treating reactions if you are exposed to the food.
- Wear a medical alert bracelet or necklace that describes your allergy.
- If you have symptoms of anaphylaxis, use your Epi-pen as you have been instructed, and get medical help right away.
References:
Du Toit G et al: Randomized trial of peanut consumption in infants at risk for peanut allergy. N Engl J Med. 372(9):803-13, 2015
Dunlop JH et al: Epidemiology of food allergy. Immunol Allergy Clin North Am. 38(1):13-25, 2018
Grief SN: Food allergies. Prim Care. 43(3):375-91, 2016
Gupta M et al: Diagnosis of food allergy. Immunol Allergy Clin North Am. 38(1):39-52, 2018
Järvinen KM et al: Anaphylaxis avoidance and management: educating patients and their caregivers. J Asthma Allergy. 7:95-104, 2014
Jones SM et al: Food allergy. N Engl J Med. 377(12):1168-1176, 2017
Kattan JD et al: Optimizing the diagnosis of food allergy. Immunol Allergy Clin North Am. 35(1):61-76, 2015
Wright BL et al: Clinical management of food allergy. Pediatr Clin North Am. 62(6):1409-24, 2015
Learn more about food allergy from these websites:
U.S. Food & Drug Administration
American College of Allergy, Asthma & Immunology
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