What is the recommended treatment for an infant with a suspected milk allergy?

Management of Milk Allergy in Infants

For breastfed infants with suspected milk allergy, continue breastfeeding while the mother eliminates all cow's milk and dairy products from her diet; for formula-fed infants, switch to an extensively hydrolyzed formula as first-line treatment. 1, 2

Breastfed Infants: Maternal Elimination Diet

The mother should completely eliminate all sources of cow's milk protein from her diet, including milk, cheese, yogurt, butter, and hidden sources in processed foods. 1, 2 This approach preserves the benefits of breastfeeding while addressing the allergic condition, as proteins from the maternal diet transfer into breast milk in sufficient quantities to trigger reactions. 1, 2

Implementation Steps:

• Symptoms typically improve within 72-96 hours to 1-2 weeks of strict maternal dietary elimination. 1, 3
• Refer the mother to a registered dietitian to ensure nutritional adequacy while avoiding cow's milk proteins, with particular attention to calcium supplementation. 1, 2
• After 1-2 weeks of elimination, perform a rechallenge by reintroducing cow's milk to the maternal diet to confirm the diagnosis before implementing longer-term dietary restriction. 4, 2 This step is critical to avoid unnecessary prolonged elimination diets.

When Maternal Elimination Fails:

• If symptoms persist despite strict maternal elimination for 2 weeks, or if the infant has failure to thrive, discontinue breastfeeding and switch to a hypoallergenic formula. 1, 2
• Optimize skin care with moisturizers and topical steroids before attributing severe eczema solely to food allergy. 4

Formula-Fed Infants: Hypoallergenic Formula Selection

Use extensively hydrolyzed casein-based formula (eHF) as first-line treatment for formula-fed infants with milk allergy. 1, 5, 6 This has demonstrated 80-90% efficacy in clinical studies. 3

Formula Selection Algorithm:

• For mild to moderate symptoms: Start with extensively hydrolyzed formula (eHF). 1, 5
• For severe reactions, life-threatening symptoms, or failure to respond to eHF within 2 weeks: Use amino acid-based formula (AAF). 1, 5, 6
• Infants with non-IgE-mediated milk allergy (such as food protein-induced enterocolitis syndrome) are more likely to require amino acid-based formula. 4

Critical Avoidances:

• Do not use soy formula as a first-line alternative due to 20-40% cross-reactivity in infants with cow's milk protein allergy. 1, 3, 2
• Do not use goat's milk or sheep's milk as alternatives due to high protein homology with cow's milk. 1, 2
• Do not use partially hydrolyzed formulas for treatment (only for prevention in at-risk infants). 4

Diagnostic Confirmation

The diagnosis should be confirmed by observing symptom resolution with elimination and symptom recurrence with rechallenge, rather than relying solely on testing. 6, 7

Key Diagnostic Points:

• Skin prick tests and specific IgE measurements are only indicative of sensitization, not clinical allergy; false-positives are common. 4
• Double-blind placebo-controlled food challenge is the gold standard but is typically reserved for unclear cases. 6
• For infants younger than 5 years with moderate-to-severe atopic dermatitis despite optimized topical therapy, consider food allergy evaluation for cow's milk, egg, peanut, wheat, and soy. 4

Monitoring and Follow-Up

Most infants return to their usual state of health within 3-10 days of appropriate dietary intervention. 3

Follow-Up Protocol:

• If symptoms persist despite appropriate formula change or maternal elimination for 2 weeks, refer to a pediatric allergist or gastroenterologist. 3
• Monitor growth parameters closely, as failure to thrive warrants immediate reassessment of the management strategy. 2

Reintroduction and Prognosis

Reintroduction of cow's milk protein should be attempted under medical supervision, typically after 6-12 months of elimination. 1, 3, 2

Natural History:

• Most children with milk allergy eventually develop tolerance, often during the teenage years. 4
• The timing of reintroduction should be individualized based on the severity of initial symptoms and type of reaction (IgE-mediated versus non-IgE-mediated). 1

Common Pitfalls to Avoid

• Do not implement unnecessarily restrictive maternal diets beyond confirmed allergens, as this may compromise maternal nutrition and breastfeeding ability. 4, 1, 2
• Do not discontinue breastfeeding prematurely when maternal elimination diet can effectively manage symptoms. 1
• Do not delay introduction of other allergenic foods beyond 4-6 months in the first year of life, as early introduction may prevent other food allergies. 4
• Do not assume higher IgE levels or larger skin test wheals predict more severe reactions; severity cannot be accurately predicted by testing. 4