Wheat Allergy

Wheat has several proteins that can act as allergens. These can broadly be divided into albumin and globulins and gluten. Albumins and globulins comprise about 15 to 20% of total protein in wheat and gluten constitutes 80% of all wheat protein. 

An allergic reaction could occur when any of these wheat proteins come in contact with your immune system inside your gut or respiratory system in some cases.

Depending on the kind of immune reaction involved in the allergy, wheat allergy can be of two types: IgE mediated and non-IgE mediated.

As soon as your immune system comes in contact with wheat protein, it stimulates the production of T cells (a type of antibody), which then either trigger IgE (Immunoglobulin E) antibodies to the site or eosinophils (a type of white blood cell that fights infections). 

Wheat allergies that show symptoms suddenly are usually IgE mediated, while the non-IgE type is chronic (develops gradually).

Both these allergy types can further be divided according to the conditions that they cause:

IgE mediated wheat allergy can either occur due to consuming wheat (food allergy) or inhaling wheat (respiratory allergy).

Food allergy to wheat can cause conditions like urticaria, stomach and respiratory problems or anaphylaxis. It can also cause wheat dependent exercise-induced anaphylaxis (WDEIA) in adults.

WDEIA is a rare condition in which a person shows symptoms of wheat allergy when they exercise within 4 hours of consuming wheat. It is often difficult to diagnose and shows up more in adults. Though it is called WDEIA, it may have other cofactors apart from exercise. These include alcohol, certain types of drugs like NSAIDs (non-steroidal anti-inflammatory drugs), infections or stress.

Respiratory allergy to wheat is usually seen in people who work at bakeries and are exposed to large amounts of wheat flour throughout the day. It can manifest in the form of Baker’s asthma and Baker’s rhinitis.

Baker’s asthma and rhinitis are defined as conditions that occur due to an allergic reaction to cereals including barley, rice, rye or wheat, soybean flour or contaminants or additives in any of these flours like molds, mites, proteins, enzymes and insects.

Non-IgE mediated wheat allergy causes eosinophilic gastrointestinal diseases (EGID) like 

• Eosinophilic esophagitis (EoE) - inflammation of esophagus
• Eosinophilic gastritis (EG) - inflammation of the stomach

A food allergy to wheat affects multiple organs of the body and may manifest in the form of the following symptoms within 2 hours after exposure to wheat:

• Hives
• Nausea and vomiting
• Constricted throat
• Difficulty breathing 
• Stomach pain and cramps in the abdomen
• Headache
• Diarrhoea
• Wheezing
• Swelling and redness in eyes
• Watery eyes
• Cough
• Low blood pressure
• Nasal congestion

Wheat allergy may worsen eczema symptoms and cause anaphylaxis in some cases. The latter shows up as:

• Tightness in chest
• Difficulty breathing
• Severe swelling in the throat
• Dysphagia
• Lightheadedness
• Loss of consciousness

Symptoms of wheat dependent exercise-induced anaphylaxis (WDEIA) include:

• Urticaria
• Severe itching
• Angioedema or swelling in the lower layer of skin
• Tightness in chest
• Flushing
• Headache
• Excessive sweating
• Inability to swallow
• Difficulty breathing
• Nausea
• Hoarseness
• Stomach pain
• Diarrhoea
• Fainting

Baker’s asthma is often preceded by rhinitis and the patients complain of the following: 

• Cough
• Wheezing
• Shortness of breath
• Irritated and watery eyes
• Runny nose
• Conjunctivitis
• Skin problems

Normally, the person does not have the above symptoms outside the bakery, but over time, the symptoms start to become permanent.

Symptoms of eosinophilic esophagitis (EoE) in adults include:

• Swelling of the food pipe that makes the food get stuck in the throat
• Dysphagia
• Chest pain
• Heartburn

Symptoms of EoE in infants and children include:

• Abdominal pain
• Difficulty to start eating solid food
• Gagging and vomiting

Symptoms of Eosinophilic gastritis (EG) include:

• Abdominal pain
• Nausea and vomiting
• Bloating
• Diarrhoea
• Loss of appetite or early satiety
• Ascites
• In severe cases, perforation or obstruction of gastrointestinal tract

Diagnosis of IgE mediated wheat allergy is done on the basis of clinical symptoms and lab tests. The latter include:

• A skin test, where a technician will introduce a tiny amount of wheat in your skin. If inflammation or a reaction occurs within 10 minutes, it is likely that you are allergic to wheat. 
• Food challenge, wherein you will be asked to consume a small amount of wheat in the lab to see if you develop any allergic reaction.
• Blood tests that look for the presence of wheat specific IgE in your blood and the levels of the IgE. For every type of wheat allergy there is a different cut off level of IgE, which is used for differential diagnosis of the condition. (Read more: Allergy test)
• If you have WDEIA, your doctor may check the level of Omega- 5 gliadin, the wheat protein responsible for this allergy, in your blood. Tryptase, an enzyme that is released in case of an allergic reaction, has been found to be high in WDEIA patients, if checked within 6 hours of the onset of symptoms. 
• A bronchial challenge test is done to diagnose baker’s asthma. In this, the patient is asked to inhale wheat to see if they show an allergic reaction. Also, your doctor may check your lung function. 
• It is a bit difficult to diagnose EoE, especially in children and infants since the symptoms develop slowly (over the course of days for EoE) and may be confused with other conditions. EoE can be identified with an IgE test or a skin prick test, however, the test is not as specific and may not show definitive results. An esophageal biopsy looks for eosinophils in the tissue and thus provides a more definitive diagnosis for EoE. (Read more: What is a biopsy)
• EG is mainly diagnosed through symptoms and biopsy of the stomach to check for the levels of eosinophils.

Currently, there is no treatment for wheat allergy. Irrespective of the type of allergy, patients are asked to learn ways to identify wheat in food products and avoid it at all costs.

Epinephrine injections are given in case of anaphylaxis and accidental exposure. Patients are usually suggested to see a doctor even if they took an epinephrine injection at home and got their symptoms under control. This is because the effects of epinephrine only last for 20 minutes. The doctor may give you other medications like antihistamines and beta-agonists to control the symptoms further.

If you have WDEIA, you may be asked to avoid exercising or the triggers for at least 6 hours after eating anything.

In case of EoE, medications may be given to reduce eosinophil levels in the body, which would help control the symptoms.

EG treatment includes elemental diet, in which easily digestible liquid formula food is given to the patient or six food elimination diet, in which the patient is asked to cut off the six major allergy-causing foods including peanuts, milk, seafood, eggs, soy and wheat.

Also, patients are given steroids to help relieve the symptoms. 

Most people get confused between wheat allergy, gluten intolerance and celiac disease. However, the three of them are different conditions. 

Wheat allergy occurs when your body elicits an immune response against one of the proteins present in wheat. 

Celiac is an autoimmune disorder where the antibodies are targeted against your own body cells, such antibodies are called autoantibodies. Specific antibodies are formed against specific cells of the body. These antibodies can be identified through blood tests for diagnostic purposes.  

Common symptoms of celiac disorder include:

• Nausea
• Vomiting
• Bloating
• Abdominal pain
• Fatty stools
• Constipation 
• Diarrhea
• Itchy skin
• Fatigue
• Iron deficiency anemia
• Anxiety or depression
• Weight loss
• Headache

Apart from antibodies, these symptoms are used to diagnose the disorder. Celiac symptoms are triggered when a person ingests gluten in any form. 

Gluten intolerance has symptoms that are similar to celiac disease. However, they may also have other symptoms like brain fog, and joint pain.

If you test negative for both antibodies against wheat and specific autoantibodies found in celiac disease, you may have gluten intolerance.