What is a food allergy?

Legume and pulse allergies are types of food allergies. Food allergy occurs when the body’s immune system wrongly identifies a food as a threat. When this happens, the body releases chemicals, such as histamine, in response. It is the release of these chemicals that causes symptoms.

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What are the symptoms of a food allergy

The symptoms of a food allergy usually come on quickly, within minutes of eating the food.

Mild to moderate symptoms may include:

  • a red raised rash (known as hives or urticaria) anywhere on the body
  • a tingling or itchy feeling in the mouth
  • swelling of lips, face or eyes
  • stomach pain or vomiting.

 

More serious symptoms are often referred to as the ABC symptoms and can include:

  • AIRWAY – swelling in the throat, tongue or upper airways (tightening of the throat, hoarse voice, difficulty swallowing).
  • BREATHING – sudden onset wheezing, breathing difficulty, noisy breathing.
  • CIRCULATION – dizziness, feeling faint, sudden sleepiness, tiredness, confusion, pale clammy skin, loss of consciousness.

 

The term for this more serious reaction is anaphylaxis (anna-fill-axis).

In extreme cases there could be a dramatic fall in blood pressure. The person may become weak and floppy and may have a sense of something terrible happening. Any of the ABC symptoms may lead to collapse and unconsciousness and, on rare occasions, can be fatal.

Most healthcare professionals consider an allergic reaction to be anaphylaxis when it involves the ABC symptoms.

Getting a diagnosis

If you think you may be allergic to a legume, see your GP who can refer you to a specialist allergy clinic if needed. They can find a clinic in your area from the British Society for Allergy and Clinical Immunology (BSACI)

It’s important to get a referral even if your symptoms were mild because it can be hard to tell if future allergic reactions could be more serious.

Once you get a referral, the consultant will discuss your medical history and symptoms with you. They might suggest skin prick, blood tests, and food challenge tests to help diagnose the allergy and work out how serious it may be.

Some clues that you might be at higher risk are:

  • you have already had a serious reaction, with any of the ‘ABC’ symptoms
  • you have asthma, especially if it is not well controlled
  • you have reacted to a tiny amount of the food.

Treating symptoms

If you have mild allergic symptoms, you may be prescribed antihistamine medicine that you take by mouth. If you are at risk of anaphylaxis, you may be prescribed adrenaline to use in an emergency.

Adrenaline comes in pre-loaded adrenaline auto-injectors (AAIs) that are designed to be easy to use. Make sure you know how and when to use them. Ask your healthcare professional to show you how to use your specific brand of AAI. You can also find help on the manufacturer’s website where you can get a free trainer AAI to practise with.

The adrenaline auto-injectors prescribed in the UK are:

  • EpiPen
  • Jext

 

You must carry two AAIs with you at all times, as you may need to use a second one if your symptoms don’t improve after five minutes or get worse.

If you have asthma, and it is not well controlled, this could make an allergic reaction worse. Make sure you discuss this with your GP or allergy specialist and take any prescribed medicines.

Will you be allergic to more than one legume?

If you react to one member of the legume family, it’s possible you could react to another. This is known as “cross-reactivity”, where the proteins in one food are similar to those in another.

Some people with a legume allergy will only react to one legume, but some people will react to others as well. If you often eat other legumes and don’t have any symptoms, there’s no reason to suspect that you will become allergic to them and you can usually carry on eating them, but always follow the advice of your allergy specialist.

It’s difficult to know how many people are allergic to multiple legumes, as studies show varying results. One study found that five out of 100 people (one in 20) with an allergy to one legume also have an allergy to another. Other studies have higher estimates, but these depend on where the studies were done and how common these foods are in the diet.

If you have any concerns about allergies to other legumes, discuss these with your doctor or allergy specialist. They will be able to give you specific advice and talk to you about which foods you should avoid.

Avoiding legumes

When you’re shopping

To avoid any legumes you’re allergic to read the ingredient lists on food packets carefully every time you shop.

Only peanuts, soya and lupin are included in the list of top 14 major food allergens in the UK. This means they must be highlighted on food ingredients labels, in bold for example.

All other legumes and pulses are not included in the top 14 list, which means they are not highlighted, but they are listed in the ingredients.

When eating out

When you buy catered food, such as in restaurants and takeaways, speak to staff directly as they may not be aware that legumes can cause allergic reactions. Make sure you name the specific legume or pulse you’re allergic to.

Examples of legumes, pulses, and the foods they’re contained in

Download the Legumes and pulses allergy factsheet for a table that shows examples of legumes and the products you might find them in.  Remember, it is rare that you would need to avoid many of these. It’s very unusual to react to all legumes.

If you find you can eat any of the legumes listed in the table without having a reaction, then you can keep eating them.

Hidden legumes

If you have tried avoiding other legumes but are still having symptoms look out for these ingredients which can contain legumes.

  • Vegetable protein
  • Vegetable fibre

 

The following are not legumes

You don’t need to avoid these ingredients which are used as thickeners and gelling agents. They are not made from legumes and pulses.

Agar (E406) – a carbohydrate found in seaweed

Carrageenan gum (E407) – a carbohydrate found in seaweed

Gellan gum (E418) – a carbohydrate secreted by bacteria called Sphingomonas paucimobilis

Xantham gum (E415) – a carbohydrate produced by a bacteria called Xanthomonas campestris pv. campestris

 

Key messages

  • If you have symptoms after eating any legumes, visit your GP.
  • If you are prescribed adrenaline auto-injectors, carry two with you at all times.
  • Always be guided by your allergy specialist on which foods to avoid.
  • If you have asthma, make sure it is well managed. See your GP about this.

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