Patchiness and duodenal-jejunal variation of the mucosal abnormality in coeliac disease and dermatitis herpetiformis.

The incidence and degree of patchiness of mucosal abnormality in both coeliac disease (CD) and dermatitis herpetiformis (DH) is documented. As judged by both stereomicroscopy and subjective histology, patchiness occurred frequently in both CDand DH patients. In most cases the difference of abnormality was of only one grade, but in approximately 25% as assessed by stereomicroscopy and 10% as assessed by histology the difference was of two or more grades. In control subjects with normal small bowel mucosa the variation of the mucosal appearance between the duodenum and proximal jejunum was studied. Contrary to popular belief, no significant difference of villous and crypt measurements or of apparent villous "bridging" and "branching" between these two sites was found, if only well-orientated sections were studied. The stereomicroscopic appearances were also similar at these two sites, although villi tended to be broader in the duodenal biopsies. The duodenal-jejunal variation was also studied in CD and DH patients and although by both stereomicroscopy and subjective histology the appearances were similar in most patients, in approximately 33% the duodenal abnormality was the most severe and, surprisingly, the jejunal abnormality was more severe in approximately 15%. It is concluded that multiple, precisely located biopsies of both the duodenum and proximal jejunum are invaluable in the investigation of small bowel disease and in assessing response to treatment.