How long does take for abdominal distention to go down in adults with celiac disease?

Depends: All related to the amount of mucosal damage in the small intestine and the level of malabsorbtion.

70% improve in 2 wk: With strict gluten avoidance about 70% of patients will have noticeable improvement in 2 wk. At 4 to 6 wk patient should be evaluated to verify an adequate response to the gluten-free diet and assess adequacy of nutrition despite gluten avoidance.