When babies have blood in their stool, it can scare parents and doctors. This article looks at two real cases where babies had rectal bleeding but weren’t actually sick. One baby had swallowed the mother’s blood during birth, while the other had a milk allergy called FPIAP. This type of allergy happens when a baby’s digestive system reacts to cow’s milk proteins—even in breast milk if the mother drinks milk. The good news? Once parents stop giving the baby (or the breastfeeding mother stops consuming) cow’s milk, the bleeding stops. Kids naturally outgrow this allergy as they get older.

The Quick Take

  • What they studied: Why do some babies have blood in their diapers, and could it be caused by a food allergy?
  • Who participated: Two infants (babies under one year old) who were rushed to the hospital with rectal bleeding but showed no other signs of being sick
  • Key finding: One baby had swallowed maternal blood (not dangerous), while the other had a milk protein allergy that caused intestinal inflammation and bleeding. Both cases resolved when cow’s milk was removed from the diet.
  • What it means for you: If your baby has blood in their stool, it might be a milk allergy rather than something serious. Talk to your doctor about trying a milk-free diet. This condition goes away on its own as babies grow, and it’s not life-threatening.

The Research Details

This article presents two real-world cases of babies with rectal bleeding seen by pediatric doctors. The doctors carefully examined each baby, ran tests, and figured out what was causing the bleeding. In the first case, the baby had simply swallowed some of the mother’s blood during delivery, which is harmless and passes through the system naturally. In the second case, the doctors discovered the baby had a special type of food allergy to cow’s milk proteins.

This type of allergy, called FPIAP (Food Protein-Induced Allergic Proctocolitis), is different from typical allergies. It doesn’t show up on standard allergy tests because it’s not an IgE-mediated reaction—meaning it works through a different immune system pathway. The baby’s intestines became inflamed when exposed to cow’s milk proteins, causing bleeding.

What makes this case interesting is that the allergy can affect exclusively breastfed babies too. If the mother drinks cow’s milk, the proteins pass into her breast milk, and the baby’s system reacts to them. Once the mother stopped drinking cow’s milk, the baby’s symptoms improved.

This research matters because rectal bleeding in babies is scary for parents and doctors, but it’s not always a sign of serious disease. By sharing these cases, doctors help other healthcare providers recognize that a milk allergy could be the cause. This means babies can get proper diagnosis and treatment faster, reducing unnecessary tests and worry. It also shows that the solution is often simple—removing cow’s milk from the diet.

This is a case report, which means it describes real patient experiences rather than a large research study. Case reports are useful for teaching doctors about unusual or important situations, but they can’t prove something happens to everyone. The strength here is that these are real cases with clear outcomes. The limitation is that with only two cases, we can’t say how common this problem is or if the same solution works for all babies. However, the cases are well-documented and the outcomes are clear.

What the Results Show

The first infant presented with rectal bleeding but was otherwise healthy and showed no signs of illness. Investigation revealed the baby had swallowed maternal blood, likely during delivery or from a small cut in the mother’s breast during feeding. This is a benign condition that resolves naturally as the swallowed blood passes through the digestive system.

The second infant also had rectal bleeding without other symptoms of illness. Testing and careful evaluation led to a diagnosis of FPIAP—a milk protein allergy. The key discovery was that this baby’s intestines were reacting to cow’s milk proteins. Because the baby was exclusively breastfed, the proteins came from the mother’s diet. When the mother eliminated cow’s milk from her diet, the baby’s bleeding stopped and symptoms resolved completely.

Both cases highlight an important point: rectal bleeding in an otherwise healthy baby doesn’t automatically mean something is seriously wrong. The bleeding can have different causes, and some are much less concerning than parents might fear. In both cases, the babies recovered fully without needing surgery or long-term medication.

An important secondary finding is that FPIAP is self-limiting, meaning it goes away on its own over time. All children with this condition eventually outgrow the milk allergy as their digestive systems mature. This is good news for parents because it means the condition is temporary, not something the child will deal with forever. The prognosis is favorable, and the main treatment is simply avoiding the trigger food (cow’s milk) until the child naturally outgrows the allergy.

This case report aligns with existing medical knowledge about FPIAP, which is a recognized but sometimes overlooked cause of rectal bleeding in infants. Previous research has established that FPIAP is a non-IgE-mediated food allergy, meaning it doesn’t trigger the typical allergic response that shows up on standard allergy tests. This article reinforces that healthcare providers should consider milk allergy as a possible diagnosis when babies have unexplained rectal bleeding, especially in breastfed infants. It also confirms that elimination diets are effective treatment.

This article describes only two cases, so we can’t know how common this problem is or whether the same outcomes apply to all babies with rectal bleeding. The cases are helpful for teaching purposes but don’t provide statistical data about how many babies develop FPIAP or how long it typically takes for symptoms to resolve. Additionally, the article doesn’t provide detailed information about how long each baby had symptoms before diagnosis or exactly how quickly symptoms improved after dietary changes. For a complete understanding of FPIAP, larger studies following many babies over time would be needed.

The Bottom Line

If your baby has blood in their stool, contact your pediatrician for evaluation (moderate confidence). If your baby is breastfed and has rectal bleeding, ask your doctor about trying a cow’s milk-free diet for the mother as a potential treatment (moderate confidence). If your baby is formula-fed, discuss with your doctor whether switching to a specialized formula might help (moderate confidence). Don’t assume rectal bleeding means something serious—many cases resolve with simple dietary changes (high confidence).

Parents of infants with unexplained rectal bleeding should pay attention to this information. Pediatricians and family doctors should consider milk allergy as a possible diagnosis. Breastfeeding mothers whose babies have rectal bleeding should know that their own diet might be the cause. This information is less relevant for parents of older children or adults, as FPIAP primarily affects infants.

Symptoms typically improve within days to weeks after removing cow’s milk from the diet. Most babies show noticeable improvement within 1-2 weeks. Complete resolution usually occurs within a few weeks. As the child grows and their digestive system matures (usually by age 1-3 years), they naturally outgrow the allergy.

Want to Apply This Research?

  • Track daily diaper changes, noting the presence or absence of blood, color, and consistency. Also track the mother’s diet (if breastfeeding) to identify patterns between milk consumption and bleeding episodes.
  • If breastfeeding, eliminate cow’s milk products from your diet for 2-3 weeks and track any changes in your baby’s symptoms. Keep a food diary noting what you eat and your baby’s stool appearance to identify triggers.
  • Use the app to log daily observations of your baby’s diapers and any dietary changes. Set weekly check-ins to review patterns and share data with your pediatrician. Track the timeline from dietary change to symptom improvement to measure effectiveness.

This article describes real medical cases and is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. If your baby has blood in their stool or any concerning symptoms, contact your pediatrician or healthcare provider immediately for proper evaluation. Do not attempt to diagnose or treat your baby based on this information alone. Always consult with a qualified healthcare professional before making changes to your baby’s diet or feeding plan.