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.
LTPs are abundant in fruits, vegetables, nuts and cereals, and are most concentrated in the peel and seeds of plant foods.
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 and it’s important not to cut foods out of your diet if you don’t need to. You may be able to tolerate certain foods if they are peeled or the seeds have been removed—discuss this with your allergy specialist and follow their advice.
Common foods involved in LTP allergy in the UK include:
• peanuts
• tree nuts (e.g. hazelnuts, almonds, walnuts)
• apples
• stone fruits (e.g. peach, apricot, cherry, plum)
• dried fruit and dried fruit peel
• concentrated, processed, preserved, or fermented fruits or vegetables
• foods made using whole unpeeled fruits or vegetables such as smoothies,
juices, jams, desserts
• lettuce
• tomatoes and foods containing concentrated tomato (e.g. sauces)
• wheat (other allergens can cause wheat allergy, clarify with your allergy
specialist)
• mustard
• maize/corn
• mixed or multi-ingredient products that may include peels, seeds or
concentrated plant ingredients (e.g. ready meals, sauces)
• some mixed or multi-ingredient foods such as pizza, curry, pasta sauces, ready
meals and soups.
If you are unsure of what may be causing your allergic reactions, we advise keeping a food and symptom diary, noting any reactions you may have to any specific foods or food groups, and the length of time after eating these reactions occur. This may help an allergy consultant or dietician understand your history and diagnose the allergy more easily.
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:
The term for this more serious reaction is anaphylaxis (pronounced ana-fil-ax-is).
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.
AIRWAY - swelling in the throat, tongue or upper airways, hoarse voice, difficulty swallowing
BREATHING - sudden onset wheezing, breathing difficulty, noisy breathing, persistent cough
CIRCULATION - dizziness, feeling faint, sudden sleepiness, confusion, pale clammy skin, loss of consciousness or collapse
If you have an LTP allergy, you may find that you only have a reaction — or that your reaction is more serious — if you eat the food around the same time as doing certain activities or taking certain substances. These are known as “co-factors”, and they can include:
• exercise
• drinking alcohol
• taking a non-steroidal anti-inflammatory painkiller (NSAID), such as aspirin or ibuprofen
• stress, which may also make a reaction worse.
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 cofactor is involved. Some people may only react when more than one co-factor is present
at the same time, such as eating out, drinking alcohol and dancing/exercising.
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.
Some clues that you might be at higher risk of more serious reactions are:
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.
If you have mild allergic symptoms, you may be prescribed antihistamine medicine that you take by mouth. But if you are at risk of a serious allergic reaction (anaphylaxis), you may be prescribed adrenaline – the emergency medicine used to treat anaphylaxis. It is also known as epinephrine.
Because anaphylaxis can happen very quickly, adrenaline is available in different forms that are designed to be easy to use. It’s important to know exactly how and when to use your prescribed adrenaline. Healthcare professionals can show you how to use it, and there are also resources such as practice devices and videos on manufacturer websites.
Options currently available on prescription in the UK include:
You must carry two in-date forms of prescribed adrenaline at all times as a second dose may be needed if symptoms do not improve after five minutes or get worse.
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.
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