We often encounter food reactions seen in adults. Food reactions in adults can develop due to IgE-dependent, non-IgE-dependent, both IgE and non-IgE-dependent, non-IgE-dependent and non-immunological food intolerance. There are 4 different types of food allergy due to IgE. These four different food allergies present with different symptoms. In this article, we have written the types of food allergy due to IgE for you.
What are the Types of Food Allergy Due to IgE?
- Food allergy causing allergic shock
- Food allergy that shows delayed allergic shock symptoms to mammalian meats,
- Food allergy, triggered by food, triggered by exercise and developing allergic shock,
- Oral allergy syndrome.
Food allergy causing allergic shock
The first and most common is a typical anaphylactic type of food allergy. These reactions are potentially life-threatening and are characterized by a rapid onset (within 3 hours) on allergic food ingestion, and include urticaria, angioedema, bronchospasm, nausea, vomiting, sometimes diarrhea and, in severe cases, hypotension, unconsciousness, and dizziness due to shock (anaphylactic shock).
Food allergy with a reaction to mammalian meats with delayed signs of allergic shock
The second type of food allergy is a delayed anaphylactic reaction to mammalian meats. The allergenic epitope is α-gal, a carbohydrate widely expressed on non-primary mammalian proteins; these conditions are called a-gal allergy a-gal syndrome, and patients with this allergy may experience severe reactions to the anticancer drug cetuximab. A-gal syndrome is an increasing condition and is secondary to tick bites by the lone star tick. This unique type of allergy was first identified in the southern states of the United States, where it was exposed to lone star ticks and chiggers, and is increasingly being reported around the world. There is evidence from many parts of the world, including Australia, Europe and the USA, that the primary cause of this allergic response is tick bites that can itch for 10 days or more.
Diagnosis of A-gal syndrome is complex and is made by a detailed history of delayed-type allergy or anaphylaxis after eating red meat, supported by the presence of specific IgE for beef, pork, and lamb, and a negative IgE test for chicken, turkey, and fish. Skin prick tests are usually negative, but the intradermal test may be positive.
A-gal testing of IgE can be done at some academic centers. Management of this condition consists of detailed education based on both the digestion of red meat and avoidance of tick bites. Because this allergy may decrease over time if it is not exposed to tick bites any more.
Food allergy that develops allergic shock due to food, triggered by exercise
The third type of IgE-mediated food reactions is food-induced, exercise-induced anaphylaxis. Just digesting the food allergen and exercising in a short period of time, usually vigorous exercise such as jogging, but brisk walking can trigger symptoms. IgE to this nutrient must be demonstrable. Recently, it has been shown that in some cases, exercise is not the only factor triggering attacks. In some patients, the ingestion of significant amounts of culprit food in combination with other growth factors such as high alcohol or acetylsalicylic acid intake may cause IgE-mediated symptoms at rest. Therefore, food-induced exercise-induced anaphylaxis is more accurately characterized as a type of food allergy in which symptoms develop in the presence of aggravating factors, but exercise is the primary factor in all cases. Thus, diagnosis and treatment become more complex.
All these reactions can also be life-threatening as they cause anaphylaxis. All these patients should be evaluated by an allergist and well trained in the prevention and treatment of accidental exposures, including the use of SIE.
Oral allergy syndrome
The fourth condition is oral allergy syndrome, also called PFAS. Oral allergy syndrome results from cross-reactivity between aeroallergens and food. This type of allergy is also called FA type 2 and presents as symptoms of itching and rarely mild swelling limited to the oropharyngeal region, often after eating fresh fruit or vegetables. The syndrome is believed to begin with sensitivity to pollen allergens such as birch pollen (Bet v1). Bet v1 (profile) is a heat-labile protein abundant in birch pollen. It plays an important role in the selective polymerization of actin filaments in the required direction. It is an essential element for successful pollen formation and dispersion shared by most plants. This allergen cross-reacts with allergens found in multiple fruits such as apples, pears, and peaches. Another example of oral allergy syndrome is wormwood pollen cross-reacting with celery. These proteins are sensitive to stomach enzymes and protect the individual from systemic symptoms. Similarly, these proteins are heat sensitive. Therefore, patients can tolerate ingesting cooked fruits or vegetables without any symptoms.
In one survey, oral allergy syndrome was reported as the most common new-onset food allergy in adults. It is associated with a marked decline in health-related quality of life. At the molecular level, the most common allergens causing oral allergy syndrome are PR10 proteins and profilins. PR10 is found in species of the Rosaceae family such as peach, apple, pear and cherry. Although rare, an allergy to fresh fruits such as apples and peaches can be life-threatening and cause anaphylaxis. This occurs when the cross-reactive protein is a lipid transfer protein that is stable to heat and enzymes. Allergy to lipid transfer protein has been reported mostly in Europe, Mediterranean region. The diagnosis of oral allergy syndrome is made by the typical clinical presentation and can be confirmed by a fresh food prick test to fruit or vegetables and evidence of sensitivity to cross-reactive pollen.
Gastrointestinal problems with eosinophilia
Gastrointestinal disorders associated with eosinophilia can arise from IgE-mediated and non-IgE-mediated mechanisms. Such problems are limited to the gastrointestinal tract. It is characterized by increased eosinophils in gastrointestinal tract mucosal biopsies.
You can think of the condition called eosinophilic esophagitis as inflammation of the esophagus with blood cells called eosinophils. Gastrointestinal problems with eosinophilia suggest that it is based on an inflammatory response to food elicited by type 2 helper T cell inflammation and includes both IgE-mediated and non-IgE-mediated components. However, the exact pathophysiology is still unknown. EoE patients often suffer from long-standing progressive dysphagia and may suffer from food impaction.
Current recommendations for the diagnosis of eosinophilic esophagitis, manifested by inflammation of the esophagus by eosinophils, include signs of esophageal dysfunction unresponsive to proton pump inhibitor therapy and increased evidence of eosinophils in esophageal biopsies. The vast majority of patients with eosinophilic esophagitis have other atopic diseases such as allergic rhinitis, asthma, and IgE-mediated food allergies. The most common food associated with eosinophilic esophagitis in adults is milk, followed by wheat and eggs. Treatment is based on identification of trigger foods. This usually requires repeated endoscopies and biopsies after elimination of the most common foods and nutrients of which the patient suspects, followed by reintroduction of nutrients. Endoscopies and biopsies are necessary because symptoms are not always associated with pathology. In most cases, patients are also treated with orally taken topical steroids such as budesonide or fluticasone. Studies with biology continue.
Other Food Allergy Reactions
In addition, food protein-induced enterocolitis syndrome, which develops with a non-IgE mechanism, and food reactions related to non-IgE and non-immunological food intolerance can also be seen.
As a result;
- One of the food allergies in adults due to IgE can be evaluated in 4 different groups.
- There are also different groups of food allergies, which are less common in adults.