What is Oral Allergy Syndrome?
As we cross solidly into the Fall season, some people’s allergies cease to bother them while others with indoor environmental allergies (dust, dust mites) are on the rise. Interestingly, having seasonal allergies may increase a person’s likelihood of having certain food allergies and vice versa. There are many potential cross-reactions with foods that should be considered when someone has environmental allergies. Oral allergy syndrome (OAS) is caused by cross reactivity between proteins in fresh fruits, vegetables and nuts with pollens. This syndrome occurs in a large number (up to 70 percent) of people with pollen allergy. The proteins in the fruit and vegetables causing OAS are easily broken down with cooking or processing. Therefore, the OAS typically does not occur with cooked or baked fruits and vegetables, or processed fruits such as in applesauce. The main exceptions to this are celery and nuts, which may cause reactions even after being cooked.
What symptoms occur with OAS?
Most people with OAS have symptoms such as itching, burning, tingling and occasionally swelling of the lips, mouth, tongue and throat where the fresh fruit or vegetable touched. A sensation of tightness in the throat may be observed. Symptoms usually only last a matter of seconds to a few minutes, and rarely progress to anything more serious. However, some studies have shown that up to 9 percent of people with OAS may experience more severe symptoms of food allergy, and up to 2 percent may experience anaphylaxis (i.e. a severe allergic reaction which can involve breathing problems and low blood pressure). Symptoms are more likely to occur and be more severe during the season in which the responsible pollen is found.
What are the associations between foods and pollens?
Allergies to certain pollens are associated with OAS reactions to certain foods. For instance, an allergy to ragweed is associated with OAS reactions to banana, watermelon, cantaloupe, honeydew, zucchini, and cucumber. This does not mean that all sufferers of an allergy to ragweed will experience adverse side effects from all or even any of these foods. Reactions may begin with one type of food and with reactions to others developing later. However, it should be noted that reaction to one or more foods in any given category does not necessarily mean a person is allergic to all foods in that group.
Common cross reactions: environmental allergens & cross-reactive foods:
Alder Pollen: almonds, apples, celery, cherries, hazelnuts, peaches, pears, parsley.
Birch Alder: almonds, apples, apricots, avocados, bananas, carrots, celery, cherries, chicory, coriander, fennel, fig, hazelnuts, kiwifruit, nectarines, parsley, parsnips, peaches, pears, peppers, plums, potatoes, prunes, soy, strawberries, wheat, potential peanuts. *Note: Over 50% of people with birch allergy have cross-reactivity with some fruits and vegetables.
Grass pollen (Poaceae family, including Bermuda and Timothy grass varieties): chard, melon, orange, rye, tomato, watermelon, wheat, fig. Other cross-reactors: canola/rapeseed, celery, olive, peach, sunflower seed, white potato
Latex: Most common cross-reactors: avocado, banana, chestnut, kiwi, mango, melon, papaya, tomato. Other cross-reactors: apple, apricot, buckwheat, carrot, celery, dill, fig, orange, oregano, passion fruit, peach, peanut, pear, pineapple, sage, soybean, strawberry, walnut, white potato. *Note: Over 50% of people with latex allergy have other types of allergies.
Mugwort Pollen (Artemisia vulgaris--celery-mugwort-spice-syndrome): Most common cross-reactors: carrot, celery, chamomile, coriander/ cilantro, fennel, parsley, sunflower seed. Other cross-reactors: almond, anise, basil, bell pepper, black pepper, broccoli, cabbage, caraway, cauliflower, chard, dill, garlic, hazelnut, marjoram, melon, mustard, onion, oregano, paprika, peach, tarragon, thyme, walnut, watermelon
Ragweed Pollen (Ambrosia artemisifolia): Most common cross-reactors: apple, banana, cantaloupe, chamomile, honey, honeydew, melon, stevia, sunflower seed, watermelon, cucumber, zucchini, Echinacea, artichoke, dandelions, hibiscus or chamomile tea
*Some individuals may only show allergy to only one particular food, and others may show an allergic response to many foods.
Often well-cooked, canned, pasteurized or frozen food cause little to no reaction due to the cross-reacting proteins being broken down, causing delay and confusion in diagnosis as the symptoms are elicited only to the raw or fully ripened fresh food. Correct diagnosis of the allergen type/s involved is critical. OAS sufferers may be allergic to more than just pollen. Oral reactions to food are often mistakenly self-diagnosed by patients as caused by pesticides or other contaminants though they can also be a factor.
Working with an experienced functional medicine provider can help a client to identify environmental allergies as well as food allergies. Developing a holistic care plan in order to avoid long term use of oral antihistamines would be the goal. Addressing nutrition and focusing on an anti-inflammatory diet is part of the functional medicine approach with the allergic patient. With the goal of learning more about the individual’s triggers while taking into consideration the seasonal effects, working with someone who can apply a functional lens to these concerns is ideal. Antihistamines and other anticholinergics have well documented long-term effects on learning and memory and are best to be used in moderation.
