What is a cross allergy?
We speak of cross allergies, when an allergic reaction appears in contact with agents chemically related to the one to which we are already allergic. If some cross allergies are rather obvious because the foods are similar – cow’s milk allergy and goat’s milk allergy – other cross allergies relate two elements having, a priori, not much to do!
In reality, we are likely to have a cross-allergy when we come into contact with something whose structure between the proteins resembles that of something to which we are already allergic. Taking an interest in cross allergies makes it possible to highlight the more or less close links between the structures of certain elements and, thus, to prevent a possible allergic reaction.
What are the most common cross allergies?
- Cross allergies between pollen and food
When we talk about allergy to pollens, we generally distinguish 3 main families: betulaceae pollens (birch, alder), mugwort pollens and grass pollen. Obviously, it is quite possible to be allergic to these 3 pollens at the same time. Generally, people suffering from betulaceae pollen allergy are likely to develop a allergic reaction if they consume certain raw fruits (apple kiwi, pear, peach, nectarine, cerinse, apricot, etc.) or certain oilseeds (almonds, hazelnuts). People allergic to mugwort pollen should be particularly vigilant with umbelliferous vegetables (most are aromatic plants) such as celery, carrots, fennel, coriander, parsley… As for people allergic to grasses, they should beware of melon and watermelon! Generally, the allergic manifestation to pollen precedes the cross-food allergy.
- Cross allergies between two foods
Other common cross allergies include allergy to one food and another with similar proteins. THE food cross allergies the most known ? Cow’s milk and goat’s milk, even mare’s milk; peanuts and soybeans, peas, lentils, other tree nuts; sesame and hazelnut, kiwi, other seeds; fish and other fish; hazelnuts and Brazil nuts, cashew nuts; shrimp and crab, lobster; peach and apple, plum, cherry, pear; melon and banana, avocado; egg and poultry; wheat and barley, rye…
- Other cross allergies
These are not the only known cross allergies. Indeed, theallergy to latex is one of the fastest growing in recent years. In France, it is estimated today that approximately 1 to 5% of the population is allergic to latex and this particularly concerns the most exposed personnel (nurses, surgeons, patients who have undergone several surgical procedures). Since the first description of a case of systemic reaction to banana ingestion in a patient known to have a latex allergy in 1991, the relationship between reactions to latex and those to many foods has been documented. It is estimated that 21 to 58%1 latex allergies have food reactions especially to fruits and that, conversely, the risk of developing a latex allergy in case of allergy to the avocado – chestnut – banana – almond group is increased by 24 times2. The list of cross allergies between food and latex continues to grow. The riskiest foods for people allergic to latex ? Banana, avocado, kiwi, chestnut, kiwi and passion fruit…
The people allergic to dust mites can potentially develop an allergic reaction to snails, shrimp, oysters and squid.
The people allergic to cats may also be allergic to dogs, rodents, horses, cattle, pigs and pork.
The people allergic to bird feathers may be bothered by egg yolk
What are the symptoms of a cross allergy?
As is the case with a classic allergy, the symptoms of a cross allergy vary. They can be localized or in the most severe cases generalized. The most common symptoms are felt after ingesting the incriminated food: itching of the lips and mouth, labial oedema, tingling sensation in the palate or even swelling of the larynx. But a cross-allergy can also cause respiratory symptoms, skin reactions (urticaria, eczema). Cross allergies can also cause a generalized allergic reaction…which can lead to death. And, in fact, requires rapid support. To limit the risks, it can be interesting to find out about potential cross allergies!