Coeliac disease is a serious condition that affects the autoimmune system, but many people are not aware that they are suffering from the disorder and the problem often goes undiagnosed or misdiagnosed.

According to Healthista, coeliac disease develops when a body considers healthy cells as foreign, prompting an autoimmune response to "protect" the body. When gluten enters the body of a person suffering from the condition, antibodies are released that can cause damage to the lining of the gut.

Gastrointestinal problems are the most common symptoms associated with the disease. Norma McGough, director of Coeliac U.K., noted that a sufferer would feel nausea, diarrhea, constipation and stomach pains. She cautioned that these symptoms are often misdiagnosed as Irritable bowel syndrome (IBS), leaving some people suffering from coeliac to remain untreated.

People with coeliac could also experience other unpleasant symptoms that may not appear to be related to the stomach.

Another common symptom of the disease is mouth ulcers, which serve as an indication of a generally rundown system.

McGough said that people should be wary of the symptom as it can have a detrimental effect and it can become an ongoing problem for those who remain undiagnosed.

Coeliac disease can also cause extreme fatigue, which can be a sign that the body is not getting enough nutrients due to its reaction to gluten. People who are experiencing extreme tiredness are advised to undergo blood tests to determine whether their problem is caused by gluten in their system.

Skin rashes from dermatitis herpetiformis has also been known to be a symptom of coeliac disease. McGough noted that rashes mostly appear on the elbows and knees, but it can also be found elsewhere on the body. The rashes often clear up when the person with coeliac undergoes a gluten-free diet. A skin biopsy test can confirm if the rashes are a result of dermatitis herpetiformis.

People with the condition are also known to suffer from anaemia and vitamin B deficiencies as the body would not be able to properly absorb nutrients due to the damage in the lining of the gut.

Another problem associated with coeliac is a neurological condition called ataxia, which affect the body's coordination, balance and speech.

"It's an interesting area because neurological problems associated with coeliac disease highlight the wide range of manifestations and symptoms that can be triggered by gluten," McGough told Healthista.

She noted that there are ongoing studies suggesting that a gluten-free diet can alleviate problems like ataxia if the symptom is caught early.

Osteoporosis, a condition that makes the bones fragile, is one of the long-term complication of the coeliac if it goes untreated, according to Healthista. McGough noted that the symptom can also be alleviated by going on a gluten-free diet.

"Once established on the gluten free diet and sticking strictly to it, that can make a huge difference to bone health and bone density," said McGough.

Another sign that a person could be suffering from coeliac disease is depression. However, experts are still unclear about the exact link between depression and the condition.

"If you're unwell physically but you can't put your finger on exactly what's wrong and you've been back and forth to the doctor and they haven't either then there is a potential for you to be feeling depressed," McGough said.

Statistics have shown that 500,000 people from the U.K. are believed to suffer from coeliac disease without being aware of it. Other symptoms of the disease include sudden weight loss, multiple miscarriages in pregnant women, tooth damage and hair loss.

McGough advises people who are experiencing the said symptoms to undergo tests without changing their diet. After the screening test, an endoscopy will then determine whether or not a person suffers from coeliac disease.

A quiz has been created by Coeliac U.K. to help people to determine whether they are suffering from the disease.