Food allergy symptoms in adults may differ depending on the type of allergy. Food allergy symptoms show different clinical symptoms according to the types of food allergy. When food allergy types are mentioned, 4 different food allergies are seen in adults due to IgE. There are also food reactions that develop by other mechanisms.

Types of IgE-Related Food Allergies

Food allergy causing allergic shock

Food allergy that reacts to mammalian meats with delayed allergic shock symptoms,

Food allergy that develops allergic shock due to food, triggered by exercise,

Oral allergy syndrome.

Food allergy symptoms that cause allergic shock

Typical food allergy symptoms suggesting an IgE-mediated food allergy are characterized by a rapid onset (within 3 hours) and include urticaria, angioedema, bronchospasm, nausea, vomiting, sometimes diarrhea, and in severe cases hypotension, unconsciousness, and dizziness due to shock (anaphylactic shock).

Food allergy symptoms (a-gal allergy to a-gal syndrome) that react to mammalian meats with delayed signs of allergic shock

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.

Diagnosis of A-gal syndrome is complex and presents with delayed-type allergy or allergic shock symptoms 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.

Food allergy symptoms that develop into exercise-induced allergic shock

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.

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 adrenaline auto-injectors.

Oral allergy syndrome symptoms

Oral allergy syndrome results from cross-reactivity between aeroallergens and food. This type of allergy is also called type 2 food allergy, and it manifests itself as symptoms such as limited itching and rarely mild swelling of the mouth and lips, often after eating fresh fruit or vegetables.

Food Allergy Symptoms due to both IgE and non-IgE

Gastrointestinal problems with eosinophilia

In this case, gastrointestinal problems are at the forefront. It manifests itself with problems such as difficulty in swallowing after food intake, frequent vomiting and chest pain. In this table, symptoms are seen according to the area held by eosinophils in the gastrointestinal tract. In eosinophilic esophagitis in which the esophagus is involved, swallowing difficulties, vomiting and chest pain are prominent, while in the case of the large intestine, symptoms such as diarrhea, constipation, abdominal pain, bloody, mucous poop are observed.

Food protein induced enterocolitis syndrome due to non-IgE

Vomiting, nausea, abdominal pain and diarrhea are the main symptoms in this table.

Although food induced enterocolitis syndrome was originally thought to be a pediatric disease, it is now more commonly reported in adults, particularly crustaceans. This condition is found in patients presenting with delayed gastrointestinal symptoms, particularly seafood, and should be referred to an allergist for evaluation. Since food-induced enterocolitis is not IgE-mediated, serological tests for foods are negative.

Food Intolerance Symptoms

Food intolerance is not dependent on IgE and the immunological mechanism does not play a role.

Many adults presenting for evaluation for possible food allergy complain of nonspecific symptoms such as bloating, changes in bowel movements, chronic abdominal pain or fatigue. These nonspecific signs are not indicative of an IgE-mediated food allergy and are often suggestive of other types of food intolerance. Some other food-related reactions, such as in food-induced enterocolitis syndrome, can cause delayed abdominal pain and vomiting to the point of severe fatigue or even drowsiness. These patients do not have other classic food allergy symptoms, such as skin or respiratory symptoms.

As a result;

  • Food allergy symptoms in adults can be different depending on the type of food allergy.
  • While mild symptoms such as mild abdominal pain and itching may occur, it can sometimes cause symptoms such as severe allergic shock.
  • Food allergy symptoms related to eating meat and exercise can sometimes be very serious.
  • Oral allergy syndrome usually manifests itself with symptoms in the mouth and lips.