Cow's milk protein allergy (CMPA), commonly known as milk allergy, is a common food allergy among infants. It occurs when a baby's body reacts abnormally to the proteins found in cow's milk, whether introduced through breastfeeding or from cow's milk in formulas and solid foods. In Australia and New Zealand, more than 2% of infants are affected by this allergy. The good news is that most children tend to outgrow cow's milk allergies between the ages of three to five years. In this article, we will explore the various types, symptoms, treatment options, and frequently asked questions related to milk allergy.
Recognising Allergic Reactions:
Symptoms of cow's milk allergy typically manifest during the first few months of life. These symptoms often emerge within days or weeks of introducing a cow's milk-based formula into the diet. However, it's important to note that symptoms may also occur in exclusively breastfed infants if cow's milk protein from the mother's diet is transmitted in breast milk in sufficient quantities.
Allergic reactions to cow's milk and other dairy products typically fall into two categories: rapid onset and delayed reactions.
1. Rapid onset allergic reactions, referred to as IgE-mediated cow’s milk allergy, typically manifest within 15 minutes to two hours after consuming milk or dairy. These reactions are triggered by the body's allergy antibody, known as IgE, and can result in a variety of symptoms, such as:
Mild to moderate reactions:
- Swelling of the lips, face, eyes.
- Skin welts (hives/urticaria).
- Abdominal pain.
- Vomiting.
- Diarrhea.
Severe allergic reactions (anaphylaxis) can include one or more of the following:
- Difficult or noisy breathing.
- Hoarse voice or wheezing.
- Persistent cough.
- Tongue swelling.
- Swelling or tightness in the throat.
- Pale and floppy.
- Collapse.
It's important to remember that anaphylaxis is a medical emergency and requires immediate treatment with adrenaline (epinephrine), along with calling 000 for an ambulance.
2. Delayed reactions to cow's milk, known as non-IgE-mediated cow's milk allergy, typically occur a few hours to a few days after the consumption of cow's milk or any other milk product, but in some cases, they can occur up to a week later.
These reactions are triggered by components of the immune system other than IgE antibodies and may manifest with the following symptoms:
- Tummy pain or discomfort.
- Delayed vomiting and/or diarrhea.
- Itchy skin or eczema.
- Blood in the stool.
- In some cases, these reactions can present as chronic constipation, severe "colic," and severe Gastro-oesophageal reflux.
Diagnosis of Cow's Milk Allergy:
Diagnosing cow's milk allergy is typically straightforward when the reaction occurs immediately after exposure to milk products, and in such cases, no tests are needed.
However, in some cases, allergy skin tests and blood tests that measure allergen-specific antibodies to cow's milk, known as Immunoglobulin E (IgE), can be used to confirm rapid-onset allergic reactions.
It's essential to emphasize that a positive test result does not necessarily mean that your baby has an allergy, as false-positive results can occur. This is why we do not routinely perform allergy testing for every baby and instead rely more on the child's medical history and clinical features.
However, it's important to note that allergy skin tests and blood tests are not useful in diagnosing delayed reactions to milk, as these reactions are not caused by IgE.
In cases of delayed reactions to cow’s milk, the diagnosis relies solely on the child's symptoms:
- Symptoms that improve or stop when cow’s milk or milk-containing products are removed from the diet.
- Symptoms that restart when cow’s milk or milk-containing products are reintroduced into the diet.
Diagnosis should always be made in consultation with a paediatrician or clinical immunology/allergy specialist.
Managing Cow's Milk Allergy:
Management of cow's milk allergy primarily involves eliminating cow's milk and other dairy products from the diet. Most symptoms will usually resolve within two to four weeks of a cow's milk elimination diet.
While some individuals may tolerate yoghurt, cheese, or cooked or baked milk in certain foods, it's essential to consult with a paediatrician or a clinical immunology/allergy specialist before introducing these items at home.
Children with food allergies, including cow's milk allergy, should have an action plan in place to manage allergic reactions. Your medical provider will write your child an action plan, which may include:
- The administration of an antihistamine in cases of mild to moderate allergies.
- An adrenaline (epinephrine) autoinjector (EpiPen, Anapen) if anaphylaxis is suspected or confirmed.
For more information on anaphylaxis and setting up a personal action plan, visit www.allergy.org.au.
Breastfed Babies with Milk Allergy:
Babies who are exclusively breastfed may develop a milk allergy when cow's milk proteins pass through the mother's breast milk after she consumes milk or dairy products. This can result in symptoms of milk allergy in the baby. In most cases, these symptoms resolve when the mother eliminates all milk-containing foods from her diet.
However, in some instances, complete symptom resolution may require the mother to avoid soy as well since some babies allergic to milk may also have a soy allergy.
Breastfeeding mothers who remove cow's milk from their diet should seek guidance from a dietitian. Additionally, it's advisable for them to consider daily calcium and vitamin D supplements to support their nutritional needs.
Alternative Formula Options for Babies:
For formula-fed babies with cow’s milk allergy, several formula options are available. These formulas cater to infants with varying degrees of sensitivity to cow’s milk proteins.
1. Extensively Hydrolysed Formula (EHF): Available products include Aptamil AllerPro Syneo, Aptamil Gold Pepti-Junior, and Alfare (please note that Alfare will be discontinued in Australia from the end of 2023).
- EHF formulas are processed with enzymes to break down cow's milk proteins, making them unrecognizable to the immune system.
- EHF is often the primary choice for infants with cow’s milk allergy. However, it is not suitable for infants with a history of anaphylaxis to milk.
- Aptamil Allerpro is available over the counter but be mindful, this option is significantly more expensive than regular formulas.
- Your paediatrician, gastroenterologist, or allergy specialist can provide an authority script for Aptamil Pepti-Junior and Alfare formulas. These formulas are PBS subsidised, making them much cheaper than standard milk formulas.
2. Soy Protein Formula: Examples include Alula Gold Soy and Karicare Soy.
- Soy protein formulas are typically well-tolerated by most infants with a milk allergy. However, it's worth noting that some babies allergic to milk protein may also have a soy allergy, so close monitoring is advisable.
- These formulas are only recommended for babies over 6 months of age and are available over the counter.
3. Rice Protein-Based Formula: Examples include Novalac Allergy and Alula Gold Allergy.
- Rice protein-based formulas do not contain any milk proteins. They can be a suitable alternative to extensively hydrolysed or soy protein formulas.
- It's essential to note that these formulas are not suitable for babies with a rice allergy.
- Rice protein-based formulas are typically more expensive compared to standard milk formulas and are available over the counter.
4. Amino Acid Formula: Available products include Neocate, EleCare, and Alfamino.
- Amino acid formulas have the protein broken down into shorter chains or individual amino acids, making them the most hypoallergenic option available.
- Some infants may find amino acid formulas to have a different taste and odour compared to standard milk formulas.
- These formulas are typically recommended for babies who do not tolerate extensively hydrolysed formulas or soy formulas, which accounts for approximately 10% of babies with milk allergy, or for those with a history of anaphylaxis to milk.
- An authority script is required to purchase these formulas at the PBS subsidised price.
What to Expect:
The good news is that cow's milk allergy often resolves over time. Approximately 50% of children outgrow their milk allergy by the age of 1 year, and about 80% of children outgrow this allergy by the age of three to five years. Your doctor will advise you on the need for further allergy testing and food allergen challenges, which are typically conducted in hospital clinics and supervised by clinical immunology/allergy specialists.
Summary:
- Cow's milk protein allergy (CMPA) is a common food allergy in babies, affecting over 2% of infants in Australia.
- Allergic reactions can be rapid onset, occurring within 2 hours of milk ingestion, with symptoms ranging from mild rashes to severe anaphylaxis. Delayed reactions can manifest in various ways.
- Diagnosis is typically based on clinical evaluation, with skin prick testing and blood tests occasionally used for confirmation or monitoring.
- Management involves eliminating cow's milk and dairy products from the diet, including the mother's diet if breastfeeding.
- Your paediatrician, gastroenterologist, or allergy specialist can provide you with an authority script for some of the specialised formulas, making them cheaper than standard milk formulas.
- Fortunately, most children tend to outgrow this condition by the age of three to five years.
- If you suspect your child has a milk allergy, consult your paediatrician or allergy specialist for proper evaluation and guidance.
- For further information and resources on managing milk allergies, written by Australian specialists, visit www.allergy.org.au.
Frequently Asked Questions:
Is milk allergy the same as lactose intolerance?
No, they are not the same.
Lactose intolerance occurs when the lactose (sugar in milk) cannot be fully digested due to an enzyme deficiency called lactase, leading to symptoms like bloating, abdominal pain, irritability, diarrhea, and excessive gas.
Lactose intolerance involves the inability to digest the sugar in milk products, whereas milk allergy is characterized by an immunologic response to the proteins in milk.
It's essential to understand that if your baby has a milk allergy, using a lactose-free formula (which lacks lactose sugar) will not prevent or treat the milk allergy because it still contains cow’s milk proteins.
My baby has a milk allergy. Can I give them a hypoallergenic (HA) formula?
No, HA formulas are made by breaking down milk proteins into smaller components, but the immune system can still recognize them as milk proteins, potentially causing an allergic reaction.
Can I give my baby A2 formula if they have a cow’s milk allergy?
No, A2 Milk contains all of the proteins that you would find in standard cow's milk, except for the A1 beta-casein protein. Therefore, children with allergies to the proteins in standard cow's milk will not be able to drink A2 Milk.
Can I give my baby goat or sheep milk if they have a cow's milk allergy?
No, there is a lot of overlap in the allergy-causing components of goat and sheep milk and cow's milk. Approximately 90% of children will react to these milks if they have a cow's milk allergy.
Can a child have both non-IgE mediated (delayed reaction) and IgE mediated (rapid onset reaction) milk allergies?
Yes, children can have both types of milk allergy. This can be the situation, particularly in children with severe eczema.
Does my child need an adrenaline autoinjector for milk allergy?
Adrenaline is used in severe reactions of IgE-mediated food allergy (anaphylaxis) but is not used to treat non-IgE-mediated milk allergies. In general, non-IgE-mediated food allergies are not life-threatening.
Are there any allergy tests for delayed reactions to cow's milk (non-IgE mediated milk allergy)?
There are no blood or skin allergy tests that are useful for this kind of allergy. The diagnosis is made clinically and is established by eliminating milk from your baby’s diet with resolution of the symptoms and worsening symptoms once milk is reintroduced.
My older son/daughter has a cow's milk allergy. Is it safe to breastfeed my newborn?
Yes, it is safe to breastfeed your newborn. Breastfeeding is recommended, especially if the infant is at high risk of developing a milk allergy. Rates of cow's milk allergy in breastfeeding infants are lower than in formula-fed infants.
I am exclusively breastfeeding, and my child developed a milk allergy. I would like to continue breastfeeding - what should I do?
If your baby has a cow's milk allergy, eliminate all foods containing cow's milk protein, including cheese, yogurt, and butter from your diet. Occasionally, you will need to avoid soy as well. Consult a dietitian to ensure you have sufficient vitamin D and calcium intake and consider taking supplements.
Is my child likely to have a severe reaction from touching or smelling milk?
No, severe reactions from casual contact with milk are extremely rare.
Should infants with a milk allergy avoid specific foods when starting solids?
No, there's no need to delay introducing common allergenic foods, even for infants with a milk allergy.
When introducing solid foods to your baby, include allergenic foods like egg, peanut, tree nuts, soy, sesame, wheat, fish, and other seafood in an age-appropriate form by 12 months.
Studies suggest that early introduction of these foods may reduce the risk of your baby developing food allergies.
If your baby has an allergic reaction to any of these foods, stop giving that food and consult a healthcare professional.
However, if your child had a severe reaction to milk (anaphylaxis), please consult your healthcare provider before introducing allergenic foods.
Will my child grow out of their milk allergy?
Most infants and young children will grow out of their milk allergy. Approximately 50% of children outgrow it by the age of 1 year, and about 80% outgrow it by the age of three to five years. Your doctor can determine whether your child has outgrown it through allergy tests or supervised milk challenges. Children with delayed reactions are more likely to outgrow the allergy at an earlier age than those with rapid onset allergies.
Written by Dr Samuel Heitner
Useful resources:
The Australian Society of Clinical Immunology and Allergy (ASCIA) website contains useful information on food allergy written by Australian specialists: www.allergy.org.au.
FSANZ - Food Standards Australia and New Zealand for information on food labelling: www.foodstandards.gov.au