Allergy-related proctocolitis in infants: diagnostic usefulness of rectal biopsy.

To evaluate the diagnostic utility of rectal mucosal biopsies in infants with proctocolitis, we compared the clinical and histologic features of an allergy-related group (N = 36) with those of normal (N = 12) and inflammatory (N = 8) controls. Clinical features were nondiscriminatory among the three groups of patients, except for an increased absolute peripheral eosinophil count in the allergic group. Similarly, morphologic evidence of proctitis (cryptitis and crypt abscesses) and small or moderate numbers of eosinophils (less than or equal to 60 per ten high power fields) in the lamina propria of the biopsies did not discriminate among the three groups. However, large numbers of eosinophils (greater than 60 per ten high power fields) and eosinophils located in the muscularis mucosae or as the predominant cell in crypt abscesses were significantly associated with allergy-related disease. No histologic features of chronic colitis were noted in the allergy-related group. Thus, in tandem with the remainder of the clinical data, rectal mucosal biopsy is a useful adjunct in the diagnosis of allergic proctocolitis.