Neonatal transient eosinophilic colitis causes lower gastrointestinal bleeding in early infancy

Lower gastrointestinal bleeding (LGB), particularly in newborns, is of serious concern and requires urgent investigation and hospital care. Whereas allergic proctocolitis caused by food protein is a significant cause of LGB in infants with eosinophilia, there are several cases of diseases with symptoms similar to those of allergic proctocolitis but without an apparent allergic reaction influence.

We examined 2 neonates using rectosigmoidoscopy who showed eosinophilia and experienced fresh LGB soon after birth and before their first feedings. Serum eosinic cationic protein (ECP) and platelet activating factor (PAF) levels were also examined in the second case to confirm the involvement of eosinophils for its pathogenesis.

Both patients were in a clinically stable condition, and their abdomens were soft. The results of their blood analyses, abdominal radiographs, and stool cultures were normal, but they had gross eosinophilia: the eosinophil counts were 9014/mm3 (patient 1) and 1955/mm3 (patient 2). Rectosigmoidoscopy with colonic mucosal biopsy revealed nodular lymphoid hyperplasia with a pale mucosal surface and massive oozing with diffuse eosinophilic infiltration in the lamina propria. In patient 2 the serum ECP and PAF levels were elevated to 123 microg/L (normal, <14.7) and 13.1 micromol/L/min (normal, <6). A few days after intravenous hydration therapy, LGB was no longer detected, and the serum ECP and PAF levels returned to normal.

Inasmuch as these infants had LGB similar to allergic proctocolitis without any allergic reactions, we suggest that infiltrated eosinophils in the colonic mucosa could be involved in the pathogenesis of LGB in early infancy.