Oral allergy syndrome (OSA) is a well-recognized but poorly understood condition. It is characterized by a burning or painful sensation and swelling in the mouth when you eat specific foods that cross-react with the pollens to which you are allergic. Interestingly, the specific foods that cause this reaction are well established to cross-react with certain tree, grass or weed pollens, house dust mites, or latex. There are common food groups that cluster with certain nasal allergies. For example, a ragweed allergy commonly causes an oral or intestinal reaction after eating melons or bananas, but usually not other foods. Birch pollen is commonly associated with reactions to numerous foods, such as a latex allergy. The explanation for these reactions includes similarities in the structures of proteins, as well as some chemicals in food.
Although this reaction is well documented in the allergy literature, it is not commonly recognized or diagnosed by most clinicians, including some allergy specialists and many stomach specialists. Several allergy websites include lists of common foods associated with certain pollens, dust mites, or latex. However, a complete list that is easy to read or interpret can be hard to find. Also, the names of some pollens or the common links between a pollen group and a food group can be confusing.
In its classic form, the OAS should be easy to recognize. After eating a food associated with a pollen to which you are allergic, you experience an almost immediate burning sensation in your mouth or throat with or without swelling. However, it is commonly recognized that often in medicine, symptoms do not occur in the “classic” or typical manner in a specific person. Put another way, doctors are taught that “patients don’t read textbooks.” So you may experience variations of the reaction, such as swelling or tightness in your throat, burning on swallowing, a lump in your throat, or a feeling of difficulty swallowing, but you can’t relate to what you ate or what’s happening to you.
You or your doctor may misinterpret your symptoms. Often, people simply assume it happened because they had a choking spell on food they chewed poorly, swallowed too quickly, or ate or drank while it was too hot or cold. An esophageal (swallowing tube) disorder is commonly assumed to be the cause, especially acid reflux with a hiatal hernia. Acid reflux can cause an esophageal constriction called a stricture or ring that can lead to a sensation of sticking to food, but this is usually associated with symptoms of heartburn or stuck food, which then prompts an upper endoscopy or endoscopic examination. Other times, especially if it occurs in an older person, a neurological condition such as a stroke or Parkinson’s disease is blamed. Sometimes doctors decide that your symptoms are due to a nervous reaction or neurosis that has historically been called globus hysteria. The hysterical portion of the term is generally dropped these days into the shorter term globus or globus sensation, especially since it is not proven to be due to a psychiatric problem. However, globus may be the diagnosis to be made if your complaint is a lump in your throat and an “assessment” seems to yield nothing, even if OAS was not considered or excluded.
An unusual condition that has been more recently recognized in the field of gastroenterology (diseases of the stomach and intestines) that may be related to a variant of OEA is called eosinophilic esophagitis (EE) or allergic esophagitis. It was first described in the pediatric population, but is now known to occur in adults. Classically described in adolescent boys and young men presenting with food adherence episodes without symptoms of heartburn or acid reflux, it is associated with an unusual appearance of the esophagus on endoscopy (light microscopic examination of the upper gastrointestinal tract). What the doctor doing the endoscope sees is that the esophagus looks like a cat’s esophagus. That is, it looks like it has rings (cats have rings of cartilage in their esophagus, we don’t) and this is known as “ringed esophagus” or felinization of the esophagus. Microscopic signs of allergy are seen on biopsy of an esophagus with a ringed or feline appearance (which often also narrows and causes food to stick). The lining shows numerous eosinophils, a reddish-pink white blood cell, characteristic of allergic conditions. These eosinophils release chemicals like histamine that cause inflammation, pain, and tissue damage.
Food allergies are commonly found in EE, although sometimes the search for a food allergy using traditional skin tests or IgE blood tests is negative. Treatment consists of avoiding known food allergens and ingested nasal steroid sprays that are designed to be used in the nose for nasal allergies. Although not yet specifically proven, eosinophilic esophagitis (EE) may be a variant of OAE.
Eosinophilic gastroenteritis and eosinophilic or allergic colitis also exist and can be diagnosed by biopsies of the stomach, small intestine, and colon, respectively. Allergic colitis is typically seen in babies who have an allergy to cow’s milk protein. It presents as crampy abdominal pain, diarrhea, weight loss, and bloody diarrhea in an infant taking cow’s milk formula or sometimes in infants whose mothers drink a lot of cow’s milk.
Allergic gastroenteritis occurs in any age group and typically presents as abdominal pain, with or without intestinal blockage or perforation; Diarrhea; anemia; weightloss; and microscopic bleeding in the intestinal tract also known as fecal occult blood. Such bleeding is detectable only by special chemical tests on stool known as fecal occult blood tests (FOBT) or fecal guaiac test.
At least some people with food intolerances that do not make sense on the limited information from the diet diary, blood tests, biopsies, or allergy tests, may have a form of OAS. In other words, the presence of known allergies to pollen or latex may predispose to reactions to foods known to cross-react with allergies noted in OAS. However, instead of the classic symptoms of oral allergy syndrome, other stomach and intestinal symptoms or even non-gastrointestinal symptoms may occur.
Support for this concept can be found in the detailed screening of people with food intolerances. People with known allergies to pollen or latex, any known food allergies or intolerances, including gluten intolerance (celiac disease) and casein intolerance, are asked to complete a series of symptom assessments and rating scales. severely followed by a strict elimination diet. This is followed by a reassessment of symptom response while foods are reintroduced one at a time while monitoring for recurrence.
This type of analysis is the basis of the Neopaleo Specific Diet. In the near future, online symptom assessments and food intolerance screening, along with individual dietary recommendations, will be available at www.thefooddoc.com. An online diet symptom diary will also be available. A simplified table illustrating common foods that may cross-react with the broad categories of pollen allergens and latex allergy is available. Food intolerances are increasingly recognized as a common cause of illness and symptoms. Individualized specific diet recommendations and elimination diet trials may be most helpful in uncovering possible links to what you are eating and how you are feeling.
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