Background: Until recently, adult celiac disease (i.e., gluten sensitive enteropathy) was believed to be rare, but the prevalence is now estimated to reach 1 percent in some populations. Adult celiac disease is nine times more common than the childhood syndrome. The diagnosis is often delayed or missed. Patients are usually diagnosed between 40 and 50 years of age, but report that their symptoms have been present an average of 4.5 to 9.0 years before diagnosis. An estimated eight undiagnosed cases are believed to exist for every recognized case.

The Review: In genetically sensitive persons, the heightened immunologic sensitivity to gluten from wheat, barley, or rye can result in gastrointestinal and systemic symptoms. Only 5 percent of adult patients have a low body mass, and few have symptoms of malabsorption. Vague gastrointestinal symptoms such as abdominal pain, bloating, and diarrhea are common, and many cases are misclassified as irritable bowel syndrome (IBS). A substantial proportion of patients have no gastrointestinal symptoms. These patients with “silent cases” present with symptoms such as fatigue, myalgia, arthralgia, recurrent aphthous ulcers, depression, or skin rashes (especially dermatitis herpetiformis). The comorbidity of adult celiac disease with specific conditions ranges widely from 1 to 2 percent of patients with alopecia areata to nearly 90 percent for dermatitis herpetiformis (see accompanying table). Celiac disease should be considered in patients with these conditions, as well as those with a family history of the disease. The prevalence of celiac disease in first-degree relatives of diagnosed patients is 4 to 22.5 percent.

Several diagnostic serologic tests are available for adult celiac disease. Immunoglobulin G (IgG) and IgA gliadin antibodies are less sensitive than IgA endomysial antibody, but the IgA endomysial test is subject to operator error and may be negative in milder cases. The new IgA tissue transglutaminase antibody may have sensitivities of around 92 percent, and a negative predictive value of nearly 100 percent. The review recommends a diagnostic strategy of tissue transglutaminase testing first, followed by endomysial antibody testing in positive patients. Duodenal biopsy remains the definitive diagnostic test. Patients must remain on a normal diet that contains gluten until after the biopsy. Resolution of symptoms with a gluten-free diet confirms the diagnosis.

Management of adult celiac disease is based on a gluten-free diet. This can be difficult and expensive to maintain because of the pervasive use of wheat and related cereals in food. Some patients may be able to tolerate oats. Research into dietary supplements that digest gluten before it reaches the small bowel could provide alternative treatment options.

Diagnosis and treatment may improve patients' quality of life and avoid long-term complications of adult celiac disease. Although small bowel lymphoma is up to 50 times more common in this population, the overall risk of this rare condition is still low (an estimated 0.5 to 1 per million persons with adult celiac disease per year). Up to 40 percent of patients with adult celiac disease have reduced bone mineral density at diagnosis, so screening and appropriate interventions are indicated to prevent osteoporosis and fracture. One third of patients may have functional hyposplenism, requiring protection against infection with encapsulated organisms, including pneumococci and Haemophilus species. The traditional association with subfertility and reproductive problems is now questioned.

Recommendations: The authors stress the need for a greater awareness of adult celiac disease and its multiple clinical presentations and associations. In particular, adult celiac disease should be considered in cases attributed to IBS. If the diagnosis is confirmed, patients may require considerable assistance, including from voluntary agencies and support groups, to adhere to a gluten-free diet.