Is it Lactose Intolerance or Cow’s Milk Protein Allergy?

If your baby struggles with milk, it’s easy to get confused between lactose intolerance and cow’s milk protein allergy (CMPA). These conditions are very different and need different approaches.

Before cutting lactose from your child’s diet, it’s important to know the difference—so you can get the right help and support.

This blog will help you understand the two conditions and give practical guidance on spotting the difference in your little one.

What is Lactose?

Lactose is a natural sugar found in breastmilk, cow’s milk, and dairy products. Babies are born with high levels of lactase, an enzyme that digests lactose.

Most children under 5 years old have plenty of lactase, so true lactose intolerance is rare.

What is Lactose Intolerance?

Lactose intolerance happens when your child’s gut cannot properly digest lactose.

The main types:

Tip: Secondary lactose intolerance is common after a gut injury. Breastfeeding should continue, even if breastmilk contains lactose.

What is Cow’s Milk Protein Allergy (CMPA)?

CMPA is an immune reaction to the proteins in cow’s milk, not the sugar.

• IgE-mediated CMPA: Symptoms appear immediately after milk exposure.

• Non-IgE mediated CMPA: Symptoms appear 48–72 hours later, often confused with lactose intolerance.

Most babies with CMPA can still tolerate lactose, unless their gut is damaged.

Non-IgE CMPA – Diagnosis & Treatment

There aren’t any reliable blood or skin tests for non-IgE CMPA. Diagnosis usually involves:

1. Removing all cow’s milk and dairy products.

2. Monitoring symptoms.

3. Reintroducing milk under guidance to confirm the allergy.

Feeding Options:

• Breastfed babies: Mother avoids dairy and may take calcium supplements.

• Formula-fed babies: Latest guidelines now support rice-based extensively hydrolysed formulas (eHF) as a safe first-line option. If symptoms are severe or don’t improve, an amino acid formula (AAF) may be needed.

Soya formulas are not recommended under 6 months due to cross-reactivity risk.

Read more about formulas used in CMPA here. 

Symptoms: Lactose Intolerance vs Non-IgE CMPA

Tip: If your baby has skin, respiratory issues, or poor weight gain, think CMPA, not lactose intolerance.

Why Lactose Can Be Good

Even if your baby has mild issues, lactose offers benefits:

1. Supports gut health: Feeds good bacteria like Bifidobacteria & Lactobacilli.

2. Helps calcium absorption: Important for strong bones.

3. Tastes sweeter: Makes formula more palatable.

Important: Avoid removing lactose for longer than necessary—usually no more than 6 weeks.

Key Takeaways

• True lactose intolerance in children under 5 is rare.

• Most babies with diarrhea, colic, or gas have symptoms due to CMPA or temporary gut issues, not lactose intolerance.

• Removing lactose long-term can reduce gut health, calcium absorption, and formula taste.

• Rice-based extensively hydrolysed formulas are now considered a safe option for formula-fed babies with CMPA.

• If symptoms persist, speak to your healthcare professional about CMPA and the milk ladder approach.

Understanding the difference between lactose intolerance and cow’s milk protein allergy is key to getting the right treatment, helping your baby settle, and thrive!

Need help? Send us a message. The team will be in touch soon.