Outcome of infants presenting rectal bleeding: A retrospective study in a single institution

Background Although rectal bleeding in infancy ( RBI ) is not a rare phenomenon, the clinical course of RBI is not fully understood. Methods To investigate the outcome and pathogenesis of RBI , especially when concomitant with food‐protein‐induced proctocolitis ( FPIP ) and neonatal transient eosinophilic colitis ( NTEC ), 22 neonates with rectal bleeding with FPIP and NTEC from J anuary 2008 to J une 2012 were enrolled and their clinical course and mechanisms of inflammation were examined. Results Thirteen infants showed rectal bleeding after feeding and were diagnosed with FPIP , and nine infants showed rectal bleeding before feeding and were diagnosed with NTEC . Elevated peripheral white blood cell (12 685 ± 3754/μl and 30 978 ± 16 166/μl) and eosinophil (1084 ± 816/μl and 4456 ± 3341/μl) were confirmed in FPIP and NTEC , respectively. Colonoscopy revealed nodular lymphoid hyperplasia, a pale mucosal surface and oozing with diffuse infiltration of neutrophils, lymphocytes, and eosinophils in both groups. Reverse transcription polymerase chain reaction analysis revealed enhanced expression of the interleukin‐6, CCL11 , and CXCL13 genes, where CXCL13 expression was more prominent in FPIP . Mucosal infiltration by CD3 ‐ and immunoglobulin‐ A ‐ but not immunoglobulin‐ E ‐positive cells was confirmed. Among them, only one infant with FPIP developed milk allergy, whereas none with NTEC had developed milk allergy at the age of 1 year. Conclusions FPIP in infancy and NTEC are similar diseases and interleukin‐6, CCL11 , and CXCL13 may play a major role in the pathogenesis of rectal bleeding. Although the involvement of allergic reaction is possible, milk allergy was not a common outcome after 1 year of follow up.