Letter in Reply: Pediatric Crohn’s Disease in Bahrain

We thank the author for his interest in our manuscript and his valuable comments.1 We agree that the rate of extraintestinal manifestations (EIMs) in our cohort is low (8%) compared to that reported worldwide.2–5 However, the prevalence of EIMs in patients with inflammatory bowel disease (IBD) is variable.4 A study from Hungary reported EIMs in 30% of 331 patients with Crohn’s disease (CD), another study from Pakistan reported EIMs in 7% of 56 patients with IBD.4,6 Defining the true prevalence of EIMs in patients with IBD is difficult.3 Differences in study designs and methodology might explain the variation in the prevalence of EIMs.3 If only major EIMs such as arthritis, uveitis, autoimmune hepatitis, erythema nodosum, and pyoderma gangrenosum were counted, the prevalence was around 30%. If all possible systemic effects secondary to the disease or its medical therapy were included, then almost all patients will have EIMs.3,4,6 For example, in a study from Saudi Arabia, EIMs were reported in 23 (24%) out of 96 pediatric patients with CD.5 However, the most common EIMs in his cohort were oral manifestation (18 patients), and only five patients had major EIMs (eye involvements in two, autoimmune hepatitis in two, arthritis and skin vasculitis in one patient each).5 Similar to our study where only major EIMs were considered, oral manifestations were not considered as a major EIMs in other studies.2,3,6,7 In our study, if we added minor EIMs, the prevalence would reach 28.8%.2 The low rate of EIMs in our study could be probably explained by the correlation between CD severity and the tendency to develop EIMs. As those patients with EMIs in our study were already having a severe type of CD.2 Genetic and environmental effects specific to both the pediatric and adult Bahraini population may also play a role in the low prevalence of EIMs. In a study from Bahrain, out of 187 adult patients with IBD (61 patients with CD), EIMs were noted in less than 5%.7 Nevertheless, despite that the incidence of EIMs differs markedly by the duration of the disease, our patients with CD did not show a recognizable increase in the incidence of EIMs over the mean nine-year follow-up time, which might be attributed to the short duration between the appearance of symptoms and the disease diagnosis, or because of the early initiation of medical therapy.