The Mayo Clinic points out that about one-half of people with celiac disease experience weight loss. About 20 percent have constipation, and about 10 percent are obese. 

Another telltale sign, dermatitis herpetiformis -- an itchy, blistering rash – may indicate the presence celiac disease. Switching to a gluten-free diet might help get rid of the rash. A gluten-free diet isn't just a weight-loss fad. Doctors commonly recommend it to treat celiac disease. 

What You Don't Know Might Hurt You 

Many people have celiac disease and don't even know it. The Mayo Clinic reports that most people who have the condition have no or few celiac symptoms, and only about 20 to 30 percent of children who have celiac disease actually have symptoms. So while gastrointestinal symptoms are more common in children, most children with the disease will not have these symptoms. 

Even if a patient has no symptoms of the disease, he or she still may be at risk of complications, reports the University of Chicago Celiac Disease Center. 

Serious complications may include:

• osteoporosis;
• thyroid disease;
• neurological and psychiatric problems;
• nerve damage; and
• cancer.