Delayed allergic reaction to eating lemon

Lemon allergy can be caused by both IgE-mediated and IgG-dependent mechanisms, or by a combination of the two. Allergic reactions to lemon are clinically evidenced by a variety of symptoms, including digestive system disorders (cheilitis, eosinophilic esophagitis, gastroenteritis, colitis, and irritable bowel syndrome). Contact dermatitis is the only condition included among delayed allergic reactions to components of the fruit or lemon essential oils. Data on reactions to lemon and its components from the gastrointestinal tract are scarce in modern publications, and most of what is available are either a description of a single case or an analysis of the frequency of sensitization to lemon among groups of patients with allergic pathology of the digestive system.

For the first time, a clinical instance of a simultaneous acute and delayed allergic reaction to eating a lemon, manifesting as an oral allergy condition and gastrointestinal symptoms, in a 31-year-old woman, was described. The patient was diagnosed with polysensitization to various food, household, and pollen antigens, and cross-allergy to fruits of the Rutaceae family (orange, tangerine, and grapefruit). She was diagnosed with allergy and sensitivity to the allergens in the lemon pulp after undergoing a prick + prick test and an enzyme-linked immunosorbent assay. It has been found that lemon pulp contains one or more thermolabile antigens that cause both acute and delayed allergic symptoms. It has also been demonstrated that thermolabile allergens and/or particular antigenic determinants can cause delayed allergy reactions, despite the action of proteolytic enzymes of the gastrointestinal tract and hydrochloric acid. To confirm these properties of allergenic epitopes, additional research, not limited to research on thermal effects alone, but also treatment with hydrochloric acid and enzymes, is highly recommended.

Thus, for the first time, we have demonstrated that allergic reactions to lemon, with the accompanying gastrointestinal manifestations, are not limited to IgE-dependent or cell-mediated types of hypersensitivity. Clarification of specific mechanisms of allergy development and characteristics of epitopes of molecules that cause allergic reactions necessitates comprehensive diagnostics research that includes both laboratory methods (including molecular-based methods) and conducting provocative tests.

Additional studies are required to determine the sensitivity of protein molecules of allergens to the effects of various factors in the gastrointestinal tract. This will enable us to further determine the resistance of individual antigenic epitopes of lemon allergens to these factors.