Anal skin tags in inflammatory bowel disease: new observations and a clinical review

The association between intestinal Crohn's disease (CD) and specific perianal abnormalities called anal skin tags (AST) has been recognized but not well defined. Skin tags have been classified into 2 types: 1) raised, broad, or narrow, single or multiple, soft or firm, and painless, often referred to as "elephant ears"; or 2) edematous, hard, often cyanotic, tender or not, and typically arising from a healed anal fissure, ulcer, or hemorrhoid. The aims of this study were to i) better characterize those skin tags identified by the term "elephant ears" and differentiate them from other types of AST; ii) compare their prevalence in patients with CD and ulcerative colitis (UC); iii) observe the relationship of the skin tags to the location of the primary bowel disease; and iv) to discuss the value of these typical AST in making an early diagnosis of CD.

Photographs of all AST were taken when present at lower endoscopy in 170 consecutive patients with inflammatory bowel disease (IBD) seen in the private office of the senior investigator and Lenox Hill Hospital. Data was gathered with respect to major differences between the 2 types of AST. The location of the primary bowel disease for these patients was obtained from an extensive IBD computer database and review of details from charts.

Specific features of AST were described and served to favor type 1 versus type 2. AST were found more frequently in patients with CD (75.4%) as compared to patients with UC (24.6%), confirming previous observations that they are more diagnostic of CD (P = 0.005). Subset analysis revealed a trend with a greater incidence of AST in patients with colitis (46.9%) as compared to patients with ileitis (36.7%) and ileocolitis (16.3%) (P = 0.067).

We provide photographs with the most characteristic features of AST and attempt to separate elephant ears (type 1) from less typical AST (type 2) in CD. Our study confirms previous reports that AST are more commonly found in association with CD as compared with UC and more so in the presence of disease limited to the colon as compared to disease elsewhere in the bowel. Our observations support the diagnostic significance of AST heralding the diagnosis of CD when they are discovered on physical exam, especially in young people with diarrhea, abdominal pain, and/or growth retardation.