There are two groups of people that cannot eat wheat or wheat-derived products. One group is comprised of people with celiac disease, also called gluten intolerance. The other group is made up of people with allergies to wheat. While people with both of these conditions have an abnormal immune response to wheat, the responses and the resulting symptoms are very different.
People with celiac disease cannot tolerate wheat protein, gluten, either in wheat-containing food like bread or when gluten is added to other foods. When the diet contains gluten, certain kinds of white blood cells gather in the lining of the small intestine of people intolerant to gluten. They release a variety of chemicals, setting off what is known as an “inflammatory cascade” in which many damaging substances cause injury to the villi lining the small intestine. There are also “killer” T cells that attack the cells lining the intestine.
This is a chronic and ongoing process which continues as long as a person with celiac disease takes in gluten. It is caused by the cellular part of the immune system, because white blood and other cells release the substances that cause damage. Some people do not have symptoms along with this damage. Those who do usually have abdominal pain, diarrhea, and weight loss, among other symptoms. They may also have other autoimmune diseases. Or they may have problems related to the decreased ability of the small intestine to absorb calories and vitamins.
People with celiac disease do make antibodies to gluten and its components. These antibodies can be measured, and are used to diagnose celiac disease. For example, the anti-tTG test measures IgA antibodies against tTG. IgA antibodies are made in the intestine, and are not usually involved in allergic responses. It is not clear what role they play in the symptoms of celiac disease.
On the other hand, the antibodies that people with wheat allergy make when they eat wheat or gluten do cause the symptoms of an allergic reaction. Allergic individuals react to what is called an allergen by making antibodies that are type IgE and are found circulating in the blood, often in large amounts.
There is a range of allergic reactions to wheat as well as other foods. Eating wheat or gluten can cause itching, with or without swelling and redness, around the mouth. It can cause hives – itchy raised bumps appearing around the mouth, or anywhere else on the body. Wheat allergy can cause worsening of a rash called eczema, especially in children. The allergy can cause difficult and noisy breathing, as well as asthma. It can also cause gastrointestinal symptoms.
People who are very allergic can have a life-threatening reaction called anaphylaxis. This may start with itching and swelling of the mouth and hives, and progress to severe swelling of the throat and breathing tubes as well as redness and swelling of the skin. A person so affected can also have intestinal cramps, vomiting, and diarrhea. When the breathing tubes swell, an affected person may not be able to breathe. This is why it is an emergency.
Some doctors will diagnose wheat allergy with a consistent history of symptoms, a positive skin test and a positive blood test measuring IgE levels to wheat. However, unless an individual has a life-threatening reaction, food allergy may need to be confirmed by a food challenge under the supervision of a physician.
People with severe reactions to wheat not only need to avoid wheat and gluten. They also need to carry an autoinjector which contains adrenalin. The most used is called an Epi-pen®. They have to inject themselves at the first sign of throat swelling. This also means a trip to the hospital for further treatment and observation. Lesser reactions can be treated with antihistamines like Benadryl®.
Food allergies in general are more common than gluten intolerance. It has been estimated that as many as 6% to 8% of children may have food allergies. Most allergic children have allergies to multiple foods including milk, eggs, and peanuts, among other things. Around 3% of adults continue to be allergic, with peanut and other nuts, as well as shellfish and fish allergies persisting into adulthood. Wheat is not a common allergen.
There are a number of obvious differences between gluten intolerance and wheat allergy. Gluten intolerance often causes silent damage, or symptoms that may not be obviously connected to eating wheat. Wheat allergy usually causes quick reactions which occur soon after the wheat is eaten. Wheat allergy is usually outgrown. Gluten intolerance is permanent. If an allergic person eats wheat, there are medications to treat the symptoms. There is no treatment to stop damage to the intestine in people with gluten intolerance who eat wheat.
Just looking at these conditions generally, wheat allergy can look more alarming while gluten intolerance does chronic, ongoing damage.
Increasing numbers of people are being diagnosed with celiac disease. Since wheat is not a common allergen, and most children who are allergic to wheat “outgrow” the allergy, celiac disease may be more common than wheat allergy. If there is any uncertainty about what is causing a reaction to wheat, there are definite ways for a doctor to distinguish the two. So if you suspect that you may have a gluten intolerance or a wheat allergy the best thing to do is to discuss this with your doctor.