Food Allergy

What is a food allergy?

From: MedlinePlus, National Library of Medicine

A food allergy is an abnormal immune system reaction to certain foods. Your immune system normally protects you from germs. But if you have a food allergy, your immune system mistakenly reacts to certain foods as if they were harmful. This reaction is usually mild. But in some cases, it can be serious or even life-threatening.

A food intolerance is different than a food allergy. If you have a food intolerance, you also have symptoms when you eat that food. But these are typically just digestive symptoms such as bloating and gas. Also, an intolerance is not an immune system reaction.

Most food allergies are caused by:

• Cow's milk
• Chicken eggs
• Crustacean shellfish, such as shrimp, crab, lobster, and crayfish
• Fish
• Peanuts
• Sesame
• Soy
• Tree nuts, such as almonds, walnuts, pecans
• Wheat

People with a food allergy may be allergic to more than one type of food.

Who is more likely to develop a food allergy?

From: MedlinePlus, National Library of Medicine

Both children and adults can have food allergies. Some children will outgrow their food allergies. And sometimes people can develop food allergies as adult.

Certain factors can make you more likely to have a food allergy. They include:

• Having eczema, a disease that causes inflammation, redness, and irritation of the skin. Your immune system also plays a role in eczema.
• Having asthma or other allergies, such as hay fever.
• Your genes. Certain genes may influence the development of food allergies. And you are more likely to have food allergies if someone in your family has allergies, asthma, or eczema.

What are the symptoms of food allergies?

From: MedlinePlus, National Library of Medicine

If you are allergic to a food you have eaten, you may have a variety of symptoms. These symptoms are not always the same for every person. And the symptoms that you get each time you eat the food may not always be the same. For example, your symptoms may sometimes depend on how much of the food you ate.

Food allergy symptoms usually start within a few minutes to two hours after you eat that food. They may include:

In rare cases, a food allergy can cause a life-threatening reaction called anaphylaxis. It may start out with some milder symptoms, but then it becomes more serious. It can lead to:

This is a medical emergency. call the local emergency number (112 in India) if someone is having the symptoms of anaphylaxis.

• Hives
• Flushed skin or rash
• Tingling or itchy sensation in the mouth
• Face, tongue, or lip swelling
• Vomiting and/or diarrhea
• Abdominal (belly) cramps
• Coughing or wheezing
• Dizziness and/or lightheadedness
• Swelling of the throat and vocal cords
• Trouble breathing
• Narrowed airways in the lungs
• Severe trouble breathing because of swelling in the throat
• Severe lowering of blood pressure and shock ("anaphylactic shock")
• Loss of consciousness

How are food allergies diagnosed?

From: MedlinePlus, National Library of Medicine

To find out if you have a food allergy, your health care provider will

• Ask about your symptoms, family health history, and medical history, including other allergies.
• Likely do a physical exam.
• Do food allergy testing. This could involve skin testing, blood testing, a food elimination diet, and/or an oral food challenge test. An oral food challenge test is the most accurate food allergy test.

What are the treatments for food allergies?

From: MedlinePlus, National Library of Medicine

There is no cure for food allergies. The only way to prevent a reaction is to avoid eating the food that you are allergic to.

There are medicines for people with food allergies. They include:

• Medicines to reduce food allergy symptoms, including antihistamines and corticosteroids.
• Medicines to reduce allergic reactions, including severe reactions.
• Epinephrine, a medicine to treat anaphylaxis. Your provider may give you a prescription for an epinephrine auto-injector. It is a device used to inject epinephrine when someone is having symptoms of anaphylaxis. If you have been prescribed one, it's important to learn how to use it and to carry it with you at all times.

If you have a food allergy, it's a good idea to have a medical alert bracelet that says what your allergy is.

Which doctor should you see?

The suggested department for discussing Food Allergy is Allergy and Immunology, with a allergist / clinical immunologist as the relevant type of clinician. General physician / Family Medicine; paediatrician for children. Referral depends on symptoms.

This is an editorial referral starting point. The appropriate clinic depends on the person’s age, symptoms, previous diagnosis and local services. The first clinician can decide whether another specialty or a team is needed; a department label does not confirm the diagnosis.

How to prepare for an assessment

Bring a short timeline of the main symptoms: when they first appeared, whether they are constant or episodic, what seems to change them, and how they affect daily activities. Include previous reports, discharge summaries, current medicines and supplements, allergies, and any relevant family history. A dated record is more useful than trying to match every feature in an online article.

Ask the clinician what is already established and what remains uncertain. If a test is suggested, ask what question it answers, what its limitations are and how the result would change the next step. The information here is not an instruction to arrange every possible test. In children, bring growth, developmental and school information if it is relevant to the concern.

• Does the history suggest an allergy, an immune problem or another explanation?
• How would any proposed allergy or immune test change care?
• Is an individual emergency plan needed, and who should understand it?

Treatment discussions and follow-up

Where the source describes treatments, these are an overview of possible care, not a prescription for an individual. Ask which option applies to the confirmed diagnosis, what benefit is expected, what adverse effects to watch for and how progress will be assessed. Availability, approvals and local practice can differ from the country described in the source.

Before leaving the appointment, clarify the next review date, who will communicate results, and whom to contact if the situation changes. Discuss difficulties with sleep, work, school, mobility, eating or emotional wellbeing when these are relevant. Practical support may require coordination between the treating clinician and other services.

When to seek emergency help

Severe breathing difficulty, collapse, new stroke-like symptoms, a seizure that is prolonged or repeated without recovery, uncontrolled major bleeding, or an immediate risk of self-harm require emergency help. In India, call 112 or reach the nearest emergency department. This is a general, non-exhaustive warning list; it is not a condition-specific triage tool.