Blood in Stool / Iron Deficiency

During the first few months of an infant’s life they often have colored stools, including yellow, green and even stools with streaks of blood (hematochezia).

This may be frightening for parents, but it is relatively common in babies and is usually not a sign of a serious problem (Patel & Kay 2022 Patient education – rectal bleeding).

However, when it is chronic it can lead to iron deficiency (ID) or iron deficiency anemia (IDA). Iron-deficiency with and without anemia may be a manifestation of chronic undiagnosed CMPA (Ferrara et al 2006).

In one study they reported ~16% of young children had iron deficiency with or without anemia due gastrointestinal blood loss related to cow’s milk allergy (Ferrara et al 2006). In a more recent study they reported that ~14% of children <4 years with IDA had CMPA (Lai & Yang 2018).

Blood in Poo / Stools & CMPA

What causes blood in stools and iron deficiency in infants?

Straining when passing a hard stool, for example, can cause small tears in the area around the anus, or anal fissures, which can result in blood streaks in the nappy. Chronic CMPA can also be a cause of hematochezia and ID with or without anemia, in young children.

This can be due to chronic blood loss resulting from damage to the gastrointestinal tract related to CMPA. Some of the complex condition like food protein-induced enterocolitis syndrome or eosinophilic gastrointestinal disease have been known to cause blood loss (Lai & Yang 2018).

Could these be a symptom of Cow’s Milk Protein Allergy?

Blood in stools or hematochezia which leads to ID or IDA can occur in some cases of severe undiagnosed CMPA e.g., non–IgE-mediated CMPA with gastrointestinal involvement (Koletzko et al 2012).

However, hematochezia is commonly seen in infants, and CMPA is therefore not the only cause (Bajerova et al 2022). A specific diagnostic work up according to the presence of other symptoms such as, infection, anal fissure or a rectal prolapse, is therefore recommended (Bajerova et al 2022).

An immediate referral to a physician is required in sick infants with haematochezia.