An oral allergy to fruit is classified as a type I hypersensitivity reaction in which the mucosa, or lining, of the mouth becomes immediately inflamed upon contact. A number of fruits are known to cause burning and itching of the mouth and lips, but can also cause breathing difficulties in extreme cases. Most individuals suffering from fruit allergies also are sensitive to other allergens, such as latex and pollen. Accidental contact with latex and pollen through food preparation can induce allergic symptoms similar to that of fruit allergy.
Clinical Characteristics
An article in the April 2007 issue of “Allergy” reported on the clinical characteristics of peach exposure to known allergic patients through skin-prick tests, oral challenges and medical history. Sixty-seven percent of the participants showed a positive reaction to peach pulp and 36 percent were allergic to canned peaches. The most common symptom in the participants was oral allergy syndrome, or OAS, which affected 86 percent of the patients. OAS is a condition characterized by burning or itching of the lips, mouth, and/or throat immediately upon contact with the fruit. In more severe case, swelling of the lips, tongue, and uvula can occur, possibly accompanied by restriction of the throat. The second most common symptom of peach exposure, affecting 61 percent of the patients, was urticaria, more commonly known as hives.
Prunoideae Family
Peach, cherry, apricot and plum are related species grouped together in a family called Prunoideae. A study in the October 1994 issue of the “Journal of Allergy and Clinical Immunology” described the cross-reactivity of fruits between the Prunoideae family to identify their major allergens. The researchers identified a relatively small protein that enhances allergic reactions through binding to IgE, a molecular signal produced by white blood cells when exposed to allergens. When these two chemical mediators come together, they synergistically promote a cascade of events culminating in OAS.
Atopic Eczema and Fruit Allergy
A study published in the April 2006 issue of “Clinical & Experimental Allergy” investigated the relationship between atopic eczema, a chronic skin disorder characterized by inflamed, scaling and itchy rashes, and food allergies. The researchers evaluated the reactions of 80 atopic eczema sufferers to common food allergens, including fruit, and found that 65 percent of them showed visual signs of a hypersensitivity reaction, but only half of those responded positively to a skin-prick test. All were symptomatic within one hour and most showed characteristic signs of OAS.
Latex-Fruit Syndrome
Thirty to 50 percent of individuals who are allergic to natural rubber latex are also allergic to some sort of plant-derived food, most often fruits. This can be a problem for allergic individuals who unknowingly consume foods prepared by a person wearing latex gloves. This relationship between allergies to latex and plant-derived foods is called latex-fruit syndrome, or LFS. A study in the January 2003 issue of “Current Allergy and Asthma Reports” identified a protein common to banana, avocado and kiwi as the primary plant-derived allergen in LFS. This protein, a class I chitinase, cross-reacts with a protein called hevein, an antifungal protein isolated from the rubber-tree, Hevea brasiliensis. It is not uncommon for those in institutions with a suspected oral fruit allergy to be diagnosed with a latex allergy instead due to food preparation.
References
- “Allergy”; Peach Allergy Pattern: Experience in 70 Patients; J. Cuesta-Herranz, et al.; April 2007
- “Journal of Allergy and Clinical Immunology”; Allergenic Cross-Reactivity among Peach, Apricot, Plum, and Cherry in Patients with Oral Allergy Syndrome: An in Vivo and in Vitro Study; E. Pastorello, et al.; October 1994
- “Clinical & Experimental Allergy”; Oral Allergy Syndrome (OAS): Symptoms of IgE-Mediated Hypersensitivity to Foods; P. Amlot, et al.; April 2006
- “Current Allergy and Asthma Reports”; Latex-Fruit Syndrome; C. Blanco; January 2003
