Perianal disease is one of the most common, severe and difficult to manage complication of Crohn's disease (CD), occuring in 1 in 3 pediatric patients.1,2 Perianal fistulas can develop at any point in the disease course, even preceding the onset of gastrointestinal symptoms in 8-26% patients with CD.3, 4, 5, 6, 7 With the increasing incidence of Crohn's disease,8,9 more children will eventually present with perianal lesions. Perianal lesions such as skin tags, fissures, and hemorrhoids can become apparent before any perianal fistula is known, or they may precede the development of fistulas.10, 11, 12 Therefore, it is important to be aware of the association between perianal lesions and perianal fistulizing CD. It is also worthwhile noting that hemorrhoids are extraordinarily rare healthy children, especially prior to adolescence.13,14 In this younger age group, hemorrhoids are most commonly associated with proctitis, perianal CD, and less commonly portal hypertension or congenital abnormalities.15,16

Reliable data on the frequency of perianal fistulas in children with CD are sparse. Few population-based studies have been conducted, and none with a rigorous or systematic approach to identifying perianal fistulas.17 In population-based studies of adults with CD, approximately 11.5% (95% confidence interval [CI] 1.8%-20.6%) had perianal fistulas at or prior to CD diagnosis. There have been two retrospective studies which perianal imaging was systematically used to identify occult perianal fistulas. A study of adults with CD found 12%, and one of pediatric patients with CD identified 26%, both of which used magnetic resonance imaging (MRI) at diagnosis with blinded radiologists determining if perianal fistulas were present even among asymptomatic patients.4,5