A child presents with perianal symptoms - how often is this Crohn's disease?

Background: The cumulative incidence and predictors of future diagnosis of Crohn's disease (CD) following presentation with perianal symptoms, such as anorectal abscess, fistula or fissure, is unknown.

Methods: A 5-year retrospective review of children presenting with perianal symptoms without prior CD diagnosis was performed. Institutional cumulative incidence of CD was calculated to determine the risk of CD presenting with perianal symptoms.

Results: 1140 children presented for evaluation of an anorectal abscess (n = 232), fistula (n = 49), or fissure (n = 859). Thirty-five were later diagnosed with CD, resulting in an incidence of 3%. Prognostic indicators of future CD diagnosis included increased age per every additional year (RR 1.19, 95% CI: 1.14-1.25, p < 0.001), male sex (RR 2.12, 95% CI 1.07-4.22, p = 0.024), or perianal fistula (RR 4.67, 95% CI 2.26-9.67, p = 0.022). Among those diagnosed with CD, 57% experienced and had a documented history of a CD-associated symptom prior to perianal symptom onset. Absence of symptoms resulted in delayed diagnosis (43 vs 3 days, p < 0.02).

Conclusion: Of children presenting with a perianal symptom, three percent will eventually be diagnosed with CD. At highest risk (35%) were males aged 10 years or older with a perianal fistula; which should prompt expeditious workup.