The most common type is when the immune system makes a type of antibody called IgE to proteins in a particular food. This is an IgE-mediated food allergy. When exposure to the food occurs, symptoms start quickly. Symptoms include any or several of the following: skin itching, hives, skin swelling, nausea, vomiting, diarrhoea, breathing difficulty (wheezing, repeated throat clearing, cough, throat tightness), or anaphylaxis. Anaphylaxis is a severe allergic reaction that is rapid in onset and progressive. Symptoms of anaphylaxis involve more than one organ system from the above list. They can also include dizziness or loss of consciousness (from a drop in blood pressure) and other serious, potentially life-threatening complications. Anaphylaxis can occur with any IgE-mediated food allergy.The most common food allergens are milk, egg, wheat, soy, peanut, tree nuts, fish andCross-reactivity occurs when the proteins in one substance are like the proteins in another. As a result, the immune system sees them as the same. In the case of food allergies, cross-reactivity can occur between one food and another. Cross-reactivity can also happen between pollen and foods or latex and foods.Because of cross-reactivity, testing and diagnosis of food allergies can be challenging. Since the immune system sees similar proteins as the same, a positive skin test or blood test (serum IgE) can result in food, yet the patient may be allergic to a substance that is cross-reactive to that food. However, the individual may not have any allergic symptoms from eating that food. The individual may not have allergic symptoms from a portion of food that is cross-reactive with another food or pollen to which the individual is allergic. This is true even though they have a positive skin test or blood test for that food. This point cannot be emphasized enough. Many people end up avoiding foods because of a positive test; in some cases, they may have been eating that food without any problems.
Cross-Reactivity Between Cow’s Milk and Milk from Other
Mammals
There is a high degree of cross-reactivity between cow’s
milk and the milk from other mammals such as goats and sheep. In studies, the
risk of allergy (resulting in symptoms) to goat’s milk or sheep’s milk in a person
with cow’s milk allergy is about 90%.
The risk is much lower, about 5%, for allergy to mare’s milk
(or donkey’s milk) which is less cross-reactive with cow’s milk.
Cross-Reactivity Between Foods in the Same Animal Group
Cross-reactivity is uncommon between foods in the same
animal group. For example, most people with an allergy to cow’s milk can eat
beef, and most people with an allergy to eggs can eat chicken without any
symptoms of the respective meats. techiesin
Cross-Reactivity Between Peanut and Other Legumes (Soy and Beans)Peanuts and soybean are in the legume family, which includes beans and lentils. A common question for people with an allergy to peanuts is whether they can eat soy-based foods or other beans. More than 50% of peanut-allergic individuals will have a positive skin test or blood allergy test to another legume (soy, other beans), but it turns out that 95% of them can tolerate and eat the cross-reactive legumes. Many years ago, it was common to recommend the avoidance of legumes, including soy, because of a peanut allergy, but this practice has been proven unnecessary. As noted above, peanuts are legumes unrelated to tree nuts (almonds, walnuts, cashews, etc.). However, about 35% of peanut-allergic toddlers in the U.S. have or will develop a tree nut allergy. It is common to be “co-allergic” to tree nuts if a child is peanut allergic. Doctors thus recommend that young children avoid tree nuts if they are peanut-allergic. Safety is also a concern. Young children may struggle to distinguish a tree nut from a peanut. Thus, there is the potential for cross-contamination of tree nut products with peanuts. We have investigated whether the common occurrence of allergy to both peanut and tree nuts is due to allergen cross-reactivity. At least one study revealed that there MAY be some cross-reactive parts of the allergic proteins in a joint. But true cross-reactivity is unknown. However, the more significant issue is that allergy to tree nuts is common in peanut-allergic. Doctors should watch for tree nut allergy in peanut-allergic individuals. Their recommendations should be made on an individual basis.The same hold for peanut allergy and allergy to seeds such as sesame seed. There are a few individuals who are allergic to both. This is likely due to more than one food allergy in highly allergic individuals rather than cross-reactivity. For tree nuts, there is a high degree of cross-reactivity between cashew and pistachio and walnut and pecan. Most people who are allergic to one tree nut. marketingmediaweb