Often, after successful treatment of bacterial overgrowth, a relapse occurs, i.e., the reappearance of bacteria in areas of the small intestine that should be free of microorganisms. For the patient, this usually means a recurrence of symptoms.
In most cases, this recurrence is facilitated by pre-existing conditions and/or previously untreated underlying causes of bacterial overgrowth.
The most common causes of relapse and the need for repeat treatment are disorders of small bowel motility (migrating motor complex dysfunction) or anatomical causes (e.g. previous surgery, adhesions, ileocecal valve defects or resection, increased intestinal elasticity due to collagen synthesis disorders such as Ehlers-Danlos syndrome).