It's pretty common these days to hear people in restaurants and stores say they have a "gluten allergy" and therefore require gluten-free products, but the problem is that there's really no such thing as a gluten allergy: medical science doesn't use the term, and most gluten reactions don't involve true allergic reactions anyway.
So what do people mean when they say they have a gluten allergy? Well, they're likely using the term as shorthand for one of the recognized medical conditions that involves immune system reactions to gluten. Here are the five conditions (plus one term that's been used interchangeably with some of the others) that fit the bill:
- Celiac disease. This may be the best-known form of "gluten allergy," even though it's most definitely not an allergy. Celiac disease (sometimes also called "celiac sprue") is a serious autoimmune disorder for which the only current treatment is lifelong avoidance of gluten-containing foods.
When you have celiac disease and consume gluten (a protein found in the grains wheat, barley and rye), the gluten triggers your immune system to attack the lining of your small intestine, eventually eating away that lining in a process known as villous atrophy. The condition often causes symptoms in your digestive system but can affect other parts of your body, too. Nearly 1% of Americans suffer from celiac disease. Learn more:
‣ What Is Celiac Disease?
‣ How Common Is Celiac Disease?
- Non-celiac gluten sensitivity. Gluten sensitivity, also known as "non-celiac gluten sensitivity," is the new kid on the block: when someone who doesn't have celiac disease says she has a "gluten allergy," it's pretty likely she means she has non-celiac gluten sensitivity.
Medical science is just now beginning to recognize that some people who definitely don't have celiac disease nonetheless definitely do experience nasty symptoms when they consume foods that contain gluten. The condition can closely mimic celiac disease, making an accurate diagnosis a bit of a challenge.
Right now, there's no accepted way to diagnose non-celiac gluten sensitivity (although researchers are working on it), but once there is, some clinicians believe the number of people with this form of "gluten allergy" will dwarf the number with the celiac disease form of "gluten allergy." Again, as with celiac disease, the only current treatment for non-celiac gluten sensitivity is to avoid gluten entirely. Learn more:
‣ What Is Gluten Sensitivity?
‣ How Many People Have Gluten Sensitivity?
‣ Gluten Sensitivity vs. Celiac Disease
- Gluten intolerance. This is the term that's been used interchangeably with some of the the others. Once upon a time, people said they had a "gluten intolerance" when they tested negative for celiac disease but still found they couldn't eat gluten-containing foods. "I'm gluten-intolerant I can't eat gluten!" they announced, and the term "gluten intolerance" grew in prominence (and of course in Google searches).
In some cases, the term has been used to mean "celiac disease" (and of course to mean "gluten allergy"), which just makes things more confusing. But these days, researchers and clinicians are coalescing around use of the term "non-celiac gluten sensitivity" instead of "gluten intolerance" for people who don't have celiac disease, but who do suffer symptoms from gluten. Ultimately, the term "gluten intolerance" will likely fall out of fashion entirely. Learn more:
‣ What Is Gluten Intolerance?
- Dermatitis herpetiformis. This is what's known as the "gluten rash." Dermatitis herpetiformis is an incredibly itchy skin rash that occurs when you eat gluten. Since many people associate rashes with allergies, it's not a far stretch when people call dermatitis herpetiformis a form of "gluten allergy," although it's not a true allergy like celiac disease, dermatitis herpetiformis is autoimmune in nature (indicating an attack by your own immune system in response to gluten ingestion).
If you have a dermatitis herpetiformis diagnosis plus positive celiac blood tests, you're considered to have celiac disease as well. Regardless, a diagnosis of dermatitis herpetiformis means you need to avoid gluten to keep your rash under control. Learn more:
‣ Dermatitis Herpetiformis, the Gluten Rash
‣ Do You Have Dermatitis Herpetiformis? These Photos May Help
- Gluten ataxia. Gluten ataxia involves an attack by your immune system on your brain and neurological system in response to consumption of gluten-containing foods pretty scary stuff. The autoimmune condition is quite rare (although it may be growing in prevalence), but it falls under the overall "gluten allergy" umbrella.
People with gluten ataxia need to follow the gluten-free diet to avoid further neurological damage. Learn more:
‣ What Is Gluten Ataxia?
‣ How Many People Have Gluten Ataxia?
- Wheat allergy. Wheat allergy actually is a true allergy, but while some people refer to it as a "gluten allergy," the allergic reaction actually involves more components of wheat than just the gluten protein. The allergy is more common in children than adults.
People who are allergic to wheat need to avoid that grain, but can usually eat barley and rye, the two other gluten grains. Learn more:
‣ What Is Wheat Allergy?
‣ Wheat Allergy vs. Gluten Allergy
As you can see, someone reporting that she has a "gluten allergy" actually may have any one of a bunch of different conditions. Still, there's one unifying factor in all five of these gluten allergy manifestations: the treatment generally involves avoiding foods with wheat in them.
For a checklist that can help you compare the symptoms of the different conditions (and consider where your symptoms may fall), see: Gluten Allergy Symptoms
Ludvigsson J. et al. The Oslo definitions for coeliac disease and related terms. Gut. 2013 Jan;62(1):43-52. doi: 10.1136/gutjnl-2011-301346. Epub 2012 Feb 16.