Cross Allergies
These are allergies to substances that are chemically similar. Thus, a person allergic to cow’s milk is very likely to also be allergic to goat’s milk, because of the similarity of their proteins.
Some people who know they are allergic to a particular food prefer to refrain from consuming other foods of the same family for fear that they will trigger a serious reaction.
However, it is best to consult a doctor before making such a decision, as excluding foods can create deficiencies. Skin tests can detect cross allergies.
Here is an overview of the main cross allergies.
| If allergic to: | Possible reaction with: | Risk assessment: |
| A legume (peanut is one of them) | Another legume | 5% |
| Peanut | A nut | 35% |
| A nut | another nut | 37% to 50% |
| A fish | another fish | 50% |
| a cereal | another cereal | 20% |
| A seafood | another seafood | 75% |
| Cow’s milk | Beef | 5% to 10% |
| Cow’s milk | Goat’s milk | 92% |
| Latex (gloves, for example) | Kiwi, banana, avocado | 35% |
| Kiwi, banana, avocado | Latex (gloves, for example) | 11% |
Source: Quebec Food Allergy Association
It happens that people allergic to pollen are also allergic to fresh fruits or vegetables, or to nuts. This is called oral allergy syndrome. For example, someone with a birch pollen allergy might experience itchy lips, tongue, palate, and throat when eating a raw apple or carrot.
Sometimes swelling of the lips, tongue and uvula, as well as a feeling of tightness in the throat may occur. The symptoms of this syndrome are usually mild and the risk of anaphylaxis is low. This reaction occurs only with raw products since cooking destroys the allergen by modifying the structure of the protein.
Oral allergy syndrome is a form of cross allergy.
More and more frequent?
An allergy, really?
About a quarter of households believe that at least one family member has a food allergy, according to various surveys3. In reality, much less would be. This is because it is difficult to distinguish, without diagnosis, an allergy from another type of reaction to a food such as food intolerance.
Today, 5% to 6% of children have at least one food allergy . Some allergies lessen or disappear with age. It is estimated that nearly 4% of adults live with this type of allergy 3 .
According to a report by the Centers of Disease Control and Prevention, the US government agency responsible for prevention, the prevalence of food allergies increased by 18% among those under 18 between 1997 and 200720.
The number of serious reactions would also have increased. However, as the authors of 2 studies point out, prevalence statistics on food allergies vary greatly from one study to another. And while there seems to be an upward trend, we can’t say for sure.
Overall, diseases of allergic origin (some cases of eczema, allergic rhinitis, asthma and urticaria) are more common today than 20 years ago.
The predisposition to allergies, called atopy in medical jargon, is said to be increasingly widespread in the West.
To what can the progression of these atopic diseases be attributed?
