Allergic proctitis, a clinical and immunopathological entity.

Patients with isolated ulcerative proctitis form a heterogeneous group. Some may develop ulcerative colitis, others have a limited, benign disease. Twelve patients with isolated proctitis with a mean course of seven years were studied. All patients had a typical clinical picture consisting of a mild and intermittent course of the disease with the presenting symptom of rectal blood loss. At endoscopic examination the inflammatory process was limited to the rectal and distal sigmoid colonic mucosa with a clear upper border beyond which the mucosa of the sigmoid colon was normal. Histologically the mucosal biopsy specimens of the affected rectum resembled those of ulcerative colitis. However, in contrast with proctitis on the base of ulcerative colitis or Crohn's disease, immunoperoxidase staining revealed a markedly increased number of IgE containing cells in the lamina propria of rectal mucosa biopsies. As an IgE-mediated immune mechanism was considered to play a role in this type of proctitis, eight of the 12 patients were treated with oral administration of disodium cromoglycate (DSCG). All patients were improved by the drug. The remaining four patients with mild proctitis did not require treatment. We concluded that, in patients with isolated proctitis on clinical and immunopathological criteria, a group can be separated which responds to DSCG, a condition for which we suggest the name 'allergic proctitis'.