Allergy to fruits: what happens and how it manifests itself
OSA IS A COMMON BUT RELATIVELY SMALL TYPE OF ALLERGY
If you have an itchy mouth or skin rash or other symptoms after eating fruit, it may be an allergy to the fruit. Although fruits are not among the most common foods that cause allergic reactions, the appearance of unwanted symptoms after eating apples, bananas, peaches, kiwi and other fruits is not uncommon.
There are several reasons for a fruit allergy. On the one hand, the matter is directly in the allergenic proteins themselves, which are inside various fruits. On the other hand, such an allergy may be due to the similarity of their proteins with the proteins of other allergens, for example, pollen, latex or … other fruits. This protein similarity can confuse your immune system and it will react to everything as a potential threat.
A reaction in which a person reacts to certain fruits due to the similarity of their proteins with proteins of pollen of a certain species is called “pollen-fruit syndrome”. Its frequent manifestation is oral allergy syndrome (OSA) . Although, to be more precise, at first, when the term “oral allergic syndrome” was used for the first time (in 1987), its manifestations were not associated with pollen allergy. This refers to any allergic symptoms in the mouth, often preceded by more serious manifestations of the disease.
Be that as it may, the “pollen-fruit” syndrome can often occur both among the inhabitants of Ukraine and in Central and Northern Europe as a whole. Here one of the most common pollen allergens is birch. In turn, about 50-75% of adults with birch hay fever also react to some fruits.
Fortunately, the proteins that cause pollen-fruit syndrome are often destroyed by heat or stomach acid. Therefore, most people with such an allergy can consume baked or otherwise processed fruits. Sometimes the usual peeling of the fruit also helps to reduce the severity of the reaction. After all, allergens, but of a different class, are contained there.
Which pollen can cause a reaction to fruits and which ones:
Birch pollen cross-reacts with apples, apricots, cherries, kiwis, peaches, pears and plums.
Pollen: with oranges and other citrus fruits
Ambrosia pollen: with banana
Artemisia pollen: with peach.
ALLERGY CAUSED BY LIPID TRANSFER PROTEINS
In the Mediterranean region, where there are not many birch trees, peach allergy is common. It is provoked by lipid transfer protein (LTP). This allergen is quite stable and does not react to high temperatures. Therefore, traditional baking is unlikely to protect against the manifestation of symptoms. In addition, the very symptoms that occur with this allergy are quite strong, and the risk of a severe and life-threatening form of the disease in the form of anaphylaxis is much higher.
However, it is believed that peeling the fruit can help reduce the risk of severe reactions. After all, it contains LTP proteins.
Cross-allergy due to similarity of proteins in fruit
Just as there are cross-reactions between pollen and fruit, there can also be cross-reactions between fruits themselves due to the similarity of their proteins.
For example, not only the pollen, but also the heat-resistant LTP of the peach may be responsible for an allergy to apples.
However, due to protein similarities, people with peach allergy may also experience symptoms by eating not only apples, but also pears, apricots, plums, and cherries.
ALLERGY DUE TO LATEX
Fruits such as avocados, bananas, kiwis and others can cause allergies due to the similarity of their proteins to the allergens present in latex. At the same time, symptoms can occur both after eating and after touching these fruits.
Such cross-reactions often occur in medical or other workers who frequently wear latex gloves. The likelihood of developing a reaction to fruits in people with a latex allergy is estimated at 30-50%.
The association between latex sensitivity and food allergy is often referred to as “latex fruit syndrome” .
Avocado, banana and kiwi have the highest cross-reactivity with latex.
Among fruits, apple and papaya are considered moderate ” crosses “.
Apricot, cherry, grape, mango, nectarine, peach, pear have a low cross ability.
A BRIEF ABOUT ALLERGY TO SOME FRUIT
It is believed that the greatest number of allergic reactions are caused by the fruits of the rose family: apples, pears, plums, apricots, cherries and sweet cherries, peaches and strawberries.
Oranges and bananas are also among the common fruit-provocateurs of allergies.
But there are also cases of allergies to kiwi, coconut, date, mango, fig, grape, avocado, lychee , melon, persimmon, pineapple, pomegranate, etc.
Allergy to apples, peaches, apricots and plums
Allergies to apple, peach, apricots and plums can manifest in two different forms, depending on the allergen to which the body is reacting.
In the North of Europe, this reaction can often be the result of exposure to birch pollen. It most commonly causes a reaction to apples, but people with birch hay fever can also react to peaches, apricots, plums, and pears. Protective proteins of the PR-10 group are responsible for such cross-reactions.
But in Italy and Spain, as well as in Israel, where there is no such influence of birch pollen, allergy to Rosaceae fruits is caused by peach lipid transfer protein.
Heat-resistant LTP Pru p 3 from peach and Mal d 3 from apple are 82% identical. And peach Pru p 3 is 91% similar to apricot Pru ar 3. Specific data on Pru d 3 from plum are not yet available, but it is also believed to be highly cross-reactive with peach.
Many patients with allergies due to LTP may also have oral symptoms. But, for example, about a third of patients with apple allergy may experience reactions such as urticaria and anaphylaxis.
The amount of the allergen is affected by the variety of fruits, the degree of maturity and storage conditions. For example, ripe and freshly picked apples are known to have the highest levels of the allergen LTP, which is associated with peach allergy. Long-term storage of apples can increase the allergenic protein associated with birch pollen sensitivity. Hypoallergenic apples have not yet been withdrawn.
The risks of developing an apple allergy associated with birch pollen increase with age and double in women. But, as a rule, such an allergy occurs not earlier than adolescence.
Whereas apple allergy associated with LTP most often occurs during puberty.
Allergy to kiwi, bananas, avocados
Like other fruit allergies, kiwi, banana and avocado allergies can occur due to direct sensitization to specific fruit allergens or due to cross-reactions with similar proteins such as birch pollen or latex.
Skin, gastrointestinal, and severe systemic reactions are more common for latex allergies.
And people with sensitivity to birch pollen may experience a reaction to edible chestnut, avocado, mango.
It is worth noting that over the past decades in Europe there has been an increase in certain types of allergies, in particular to kiwi, which may be due to an increase in the consumption of this fruit.
In addition, some chemicals can also increase the allergenicity of fruits, for example, substances that are used to ripen bananas.
SYMPTOMS OF ALLERGY TO FRUIT
Most of the reactions to fruits are felt immediately after consumption, especially when it comes to raw fruits. However, in rare cases, symptoms may occur after more than an hour.
Pollen-related fruit allergies are characterized by relatively mild symptoms, such as an itchy mouth or throat, although sometimes, in rare cases, swelling of the throat and breathing problems can occur.
Usually the symptoms caused by OSA resolve within one hour. You can speed up this process by rinsing your mouth or drinking a warm drink, such as tea, but not herbal.
Sometimes these mild symptoms may be accompanied by skin reactions, asthma and rhinitis. More severe symptoms, such as digestive problems, hives and edema, and cardiovascular symptoms, are more likely to be associated with reactions caused by lipid transfer proteins and latex.
Call an ambulance if you experience the following symptoms:
- throat swelling
- narrowing of the airways
- rapid pulse
- loss of consciousness
- low blood pressure
All of these can be signs of life-threatening anaphylaxis.