Adverse reaction following the ingestion of a specific food is common for some people. The reaction is an unpleasant experience for a few, but for others the experience is life threatening.
A food allergy is an immediate manifestation of the body’s immune system when contact is made with a food substance. The body is not reacting to the food, but rather to the substance found in the food. Most often, the allergic reaction is simple and localized. The skin and oral mucosa may manifest redness, swelling, and itching. The nose may feel stuffy, and sneezing may occur. The eyes may be itchy and teary. The allergic reaction may be so serious as to involve the respiratory system, digestive system, and the blood system in an anaphylactic reaction.1,2
The prevalence of food allergy is up to 8% in children and 2% in adults in the American population. In addition, studies have shown the role of specific allergens and mediators in the immunopathogenesis of food allergy.3
Nonallergic food reactions or intolerances that do not involve the immune system may have a pharmacologic, metabolic, or toxic etiology. Food intolerance may be mistaken for a true allergic reaction; it may cause unpleasant reaction to food and does not involve the immune system. The manifestation of the reaction may look and feel like a real food allergy.4,5
A 48-year-old man presented with swelling on the right ventral surface of his tongue. Medical history was reviewed and found to be noncontributory with the exception of an intolerance to dairy products. The patient explained that whenever he ate a certain brand of chocolate chip cookies, he developed a slight swelling under the tongue that was accompanied by a slight tingling sensation within 2 to 3 minutes. Additionally, when he looked in the mirror he noticed a red swelling on the right ventral surface of the tongue. “This,” he said, “is the reason I am here.”
He was asked if this same experience had occurred previously. Without hesitation the patient stated that he was eating chocolate chip cookies a year ago and noticed a small swelling on the inside of his cheek 2 or 3 hours after eating the cookies. According to the patient, “I was not worried about the small swelling, and I was not sure when it ruptured, but the lesion was gone within three or four days.”
Figure 1a. Lesion on ventral surface of the tongue.
Figure 1b. Enlarged view of lesion.
Soft- and hard-tissue intraoral and extraoral examinations were performed. The swelling was not probed in order to avoid rupture. All other soft tissue appeared normal, the teeth showed no signs of sharp edges, and no anterior or posterior cross-bite was noted. The lesion indicated in Figures 1a and 1b had an appearance consistent with a blood-filled bulla. It was compressible and fluctuant. The area covered by the lesion was 15 mm in length, 5 mm in width, and 3 mm in height. The soft tissue surrounding the lesion was atraumatic. The patient was not in pain, but the area felt uncomfortable due to slight swelling.
The label on the chocolate chip cookies was checked, and the following ingredients were found: wheat flour, semisweet chocolate chips, soy bean oil, sugar, salt, whey (from milk), baking soda, fructose, corn starch, wheat starch, natural and artificial flavors, and caramel color.
The patient said he eats pure chocolate, peanuts, wheat products, and eggs, and never experiences an adverse reaction. Based on the patient history, chief complaint, and clinical findings, a diagnosis of food allergy or food intolerance to the ingredient(s) found in the cookies was made. The patient was advised that his case was consistent with a food allergy. He was further told the swelling would rupture on its own. After rupture of the lesion, the patient was told to rinse with warm saline solution up to 3 times a day after eating and until the lesion healed. The patient was given an appointment for 7 days later for follow-up evaluation and left in stable condition.
Figure 2. Lesion healed after 1 week.
At the follow-up appointment, it was noted the lesion had healed. The patient reported that the swelling ruptured the same day as the appointment and healed within 4 days. He experienced a slight discomfort in the area when rinsing the first 2 days after rupture. Figure 2 shows post healing in the same area.
Specific foods may be responsible for causing unusual immunologically mediated clinical responses. These allergic reactions occur by several mechanisms. The classic types are type I IgE to type IV mediated reactions. Other than the aforementioned, the nonallergic food intolerance response also has many roles in unusual food adverse reactions.6 A history of acute onset of atypical symptoms such as edema or wheezing is associated with food allergy.
A predisposed person must first be exposed to a specific food in order for IgE to be formed. Digestion of this food for the first time causes protein fragments in certain cells to produce specific IgE against that food, and the IgE then attaches to the surface of mast cells. When that food is eaten again, there is interaction between the protein and the IgE that is attached to the mast cells, triggering the release of chemicals such as histamine. This results in symptoms of an allergic reaction. If these chemicals are released in the nose and throat, an itching tongue or mouth, and possible difficulty breathing or swallowing, may result. If mast cells in the gastrointestinal tract are involved, the person may have diarrhea or abdominal pain; mast cells in the skin can produce hives or intense itching.7
Any food can trigger an allergic reaction, but the most common offenders causing true allergic reactions are milk, eggs, fish, peanuts, wheat, and shellfish. There are a few foods that cause food intolerance, and these are dairy products, nuts, yeast, and chocolate.8 Also, some individuals may demonstrate allergy reactions to flavoring agents such as cinnamon. Food allergy to chocolate is not as common as allergy to dairy products. Many people claim an allergy to ingested chocolate; headache, migraine, or localized edema are a few of the complaints. Chocolate contains many chemicals, among which are caffeine, theobromine, and phenyethylamine. Most studies in the past 2 decades indicate that chocolate can cause headache, obesity, and some emotional problems.9
No study has shown that pure chocolate can cause an allergic reaction. The higher the quality of the chocolate (cocoa liquor, cocoa butter with sugar) the less the likelihood of food intolerance. Mass-produced chocolate products, which contain less cocoa but many additives such as corn syrup, flavorings, and food dyes, are responsible for the untoward side effects.
Food allergy is an inconvenience but is manageable. With extra care the allergen, and therefore the associated symptoms, can be avoided. At the present time there is no cure for food allergy; avoidance is the only way to prevent an allergic reaction. It is wise to advise the patient to keep a record of what he or she eats in order to identify which food(s) trigger the adverse reaction. This helps to ascertain whether a specific food is contaminated or if a true allergen has caused the problem.
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3. Sampson HA, Burks AW. Mechanisms of food allergy. Annu Rev Nutr. 1996;16:161-177.
4. Bindslev-Jensen C, Skov PS, Madsen F, et al. Food allergy and food intolerance—what is the difference? Ann Allergy. 1994;72:317-320.
5. Food allergy: an overview. National Institute of Allergy and Infectious Disease, NIH Publication; No. 04-5518; July 2004, www.niaid.nih.gov.
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7. Formanek R Jr. Food allergies: when food becomes the enemy. FDA Consumer. Jul-Aug 2001. Available at: http://www.fda.gov/fdac/features/2001/401_food.html. Accessed December 3, 2005.
8. Sampson HA. Food allergy. JAMA. 1997;278:1888-1894.
9. Dotterud LK. Role of food in atopic eczema [in Norwegian]. Tidsskr Nor Laegeforen. 1996;116:3335-3340.