HowStuffWorks states that a gluten allergy is not really an allergy, but intolerance to gluten, a complex protein found in wheat, rye, oats, and barley. The most recognizable indication of gluten intolerance is manifestation of gastrointestinal problems, which include bloating, diarrhea, constipation, abdominal cramps and vomiting. Chronic fatigue, weight loss, weakness and cognitive impairments typically ensue due to the said gastrointestinal conditions.
HowStuffWorks further explains that gluten intolerance can also be recognized when the person suffers from minor to harsh skin rashes and irritation, headaches, muscle and joint pains, fluctuating moods or behaviors, depression, reproductive problems and even neurological disorders, such as seizure and numbness. Gluten intolerance, like all food intolerances, can cause malabsorption of nutrients, which then proceeds to diabetes, osteoporosis, anemia, cancers and other indications of health decline. These can be very serious and lethal, so diagnosing gluten intolerance at the earliest possible time is essential.
Finding out whether a person has gluten intolerance can be very difficult, even for medical experts, Wikipedia reports. Aside from over 250 symptoms that can indicate the occurrence of this condition, gluten intolerance is a digestive problem and not an immune system issue. Moreover, WildHealthFood says that the symptoms of other health conditions such as Crohn's disease and irritable bowel syndrome can be mistaken as manifestations of gluten intolerance. Wikipedia indicates that doing an "open challenge," wherein gluten-containing foods are consumed intentionally after being gluten-free for a given period, can help a person determine whether he is gluten intolerant.