Swollen, puffy eyes, a running nose and itching skin are all symptoms of allergic rhinitis, commonly known as hay fever. Allergic rhinitis usually results from an allergic reaction to a substance such as pollen or cat dander entering the nasal passage. However, there are other causes of allergic rhinitis, including food allergies.
Mechanism
Allergic rhinitis normally occurs when a substance such as pollen or dust, known as an allergen, enters the body, usually through the nose. The allergic person's immune system responds by releasing immunoglobulin E, or IgE, an antibody that triggers the release of histamine and other chemicals which inflame the mucus membranes, leading to nasal congestion, runny nose and watering eyes. These reactions are intended to flush the allergen, which the immune system identifies as a harmful substance, out of the body and prevent more from entering.
Food Allergies
Since the reactions of allergic rhinitis are an attempt to protect the nasal passages from allergens, it seems unlikely that this condition could be caused by food allergies. In fact, however, a small number of people suffer allergic reactions after handling raw potatoes. These reactions can include itching and other skin symptoms but also include congestion and wheezing, both common symptoms of allergic rhinitis. Similar symptoms may occur in allergic people who handle other types of fruit and vegetable, including apples, celery and carrots.
Source
A study of this type of allergic reaction published in the "Journal of Allergy and Clinical Immunology" in 1995 identified the source of allergic rhinitis in these cases. People who suffer from allergic rhinitis as part of their food allergies are usually also allergic to various types of pollen, including birch. Proteins in the uncooked food resemble the allergens in birch pollen, causing the immune system to release IgE and begin the inflammation response. The food allergy is thus related to an existing pollen allergy and produces a similar response.
Treatment
Allergies themselves cannot be cured, but it is possible to treat the symptoms. Antihistamines inhibit the action of histamine, preventing it from causing inflammation, while decongestants and corticosteroids alleviate the stuffiness and itching caused by the inflammation. Allergy sufferers who have shown a reaction to specific foods in the past should avoid them. In the case of birch pollen-related food allergies, the sensitivity appears to be to raw food. Cooked vegetables do not cause the same reaction.
