What is LTP allergy?

LTP allergy is a type of food allergy. Food allergy happens 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 the allergic symptoms.

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Foods involved in LTP allergy

Most LTPs are in the peel and pips of plant foods. Whilst fresh or raw foods can cause a reaction, the following foods are likely to contain higher levels of LTPs as they contain the peel and pips.

  • Concentrated, processed, preserved, or fermented fruits or vegetables.
  • Dried fruit peel.
  • Foods made using whole unpeeled fruits or vegetables such as smoothies, juices, jams, desserts.


If you are diagnosed with LTP allergy, you only need to avoid the foods which cause your symptoms. Not all LTP-containing foods will cause an allergic reaction for you and it’s important not to cut them out of your diet if you don’t need to. You may be able to tolerate certain foods if they are peeled or the pips have been removed. Discuss this with your allergy specialist and follow their advice.

Unfortunately, the amount of LTP in foods may vary so it can be hard to predict when a reaction may happen. Common foods involved in LTP allergy in the UK include:

  • peanuts
  • hazelnuts
  • almonds
  • walnuts
  • apples
  • stone fruits
  • dried fruit
  • lettuce
  • tomatoes
  • foods containing concentrated forms of tomato such as pizza.

What are the symptoms of LTP allergy?

Reactions to LTPs can happen after eating raw, cooked or processed foods. The symptoms are not usually immediate but typically appear within 30 minutes of eating.

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 of LTP allergy

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

Most healthcare professionals consider an allergic reaction to be anaphylaxis when it involves difficulty breathing or affects the heart rhythm or blood pressure. Any one or more of the ABC symptoms above may be present.

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 loss of consciousness and, on rare occasions, can be fatal.

More serious symptoms are often referred to as the ABC symptoms and can include:
  • right_arrow_orange_icon AIRWAY - swelling in the throat, tongue or upper airways (tightening of the throat, hoarse voice, difficulty swallowing).
  • right_arrow_orange_icon BREATHING - sudden onset wheezing, breathing difficulty, noisy breathing.
  • right_arrow_orange_icon CIRCULATION - dizziness, feeling faint, sudden sleepiness, tiredness, confusion, pale clammy skin, loss of consciousness.

LTP allergy when other factors are involved

If you have LTP allergy you may find that you only have a reaction, or the reaction is more serious, if you eat the food around the same time as doing exercise, drinking alcohol, or taking a non-steroidal anti-inflammatory painkiller (such as aspirin and ibuprofen). Stress may also make a reaction worse. These are known as ‘co-factors’.

While LTP allergy symptoms usually happen within 30 minutes of eating the food, they can sometimes be delayed by up to one or two hours depending on whether a co-factor is involved.

Getting a diagnosis

If you think you may have LTP allergy, 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.

What can mean you're at higher risk?

Some clues that you might be at higher risk of more serious reactions 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.


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 medicines you’re prescribed.

Treating symptoms

If you have mild allergic symptoms, you may be prescribed antihistamine tablets. If you are at higher 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 and training videos on the manufacturer’s website and get a free trainer device to practise with.

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.

Adrenaline auto-injectors

The adrenaline auto-injectors prescribed in the UK are:

Keeping safe with LTP allergy

The uncertainty about which foods might cause a reaction, and what might make a reaction worse, can make managing your LTP allergy particularly difficult. Always carry your prescribed medicine and make a clear allergy action plan with your allergy specialist.

Key messages

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

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