What are the management recommendations for a 3-month-old with a cow's milk protein allergy?

Management of Cow's Milk Protein Allergy in a 3-Month-Old Infant

For a 3-month-old with cow's milk protein allergy (CMPA), extensively hydrolyzed formula should be used as first-line treatment when breastfeeding is not possible or insufficient, with amino acid-based formulas reserved for severe cases or those who don't respond to extensively hydrolyzed formulas. 1

Diagnosis Confirmation

Before initiating treatment, confirm the diagnosis through:

• Symptom assessment (vomiting, diarrhea, blood in stool, excessive crying, eczema)
• Elimination of cow's milk protein from diet (maternal diet if breastfed or formula change if formula-fed)
• Improvement of symptoms after elimination
• Consider challenge testing under physician supervision for definitive diagnosis

Management Algorithm

For Breastfed Infants:

1. Continue breastfeeding with maternal dietary modification
   • Eliminate cow's milk protein from maternal diet (also consider eliminating eggs) 1
   • Maintain elimination for 2-4 weeks to assess response 1
   • Consider nutritional consultation for the mother to ensure adequate calcium intake 1
   • If symptoms persist despite maternal elimination diet, consider:
     • Expanding maternal elimination diet
     • Supplementing with hypoallergenic formula
     • If still no improvement, consider discontinuing breastfeeding and switching to hypoallergenic formula 1

For Formula-Fed Infants:

1. Switch to extensively hydrolyzed formula (eHF) 1, 2

   • Casein-based extensively hydrolyzed formulas are the first choice
   • 10-20% of infants may require amino acid-based formula 1

2. If no improvement with eHF, switch to amino acid-based formula (AAF) 1, 2

   • Particularly indicated for severe cases or those with multiple food allergies

Alternative Options:

• Rice hydrolyzed formula (rHF) may be considered where available 3, 2
• Soy formula may be considered in infants older than 6 months, but with caution due to potential cross-reactivity (20-40% risk in US patients) 1

Important Cautions:

• Avoid goat's milk and sheep's milk due to high protein sequence homology with cow's milk 1
• Avoid partially hydrolyzed formulas as they are not sufficiently hypoallergenic 4
• Do not use standard cow's milk formula or unmodified animal milks

Monitoring and Follow-Up:

• Monitor growth parameters (weight, length, head circumference) regularly 1
• Assess for symptom improvement within 3-10 days of formula change 1
• For severe cases, temporary bowel rest and intravenous fluids may be necessary 1

Reintroduction and Development of Tolerance:

• Reintroduce cow's milk protein under physician supervision 1
• Most infants with CMPA develop tolerance by 3 years of age
• Timing of reintroduction varies based on severity and type of symptoms

Complementary Feeding Considerations:

• Introduce solid foods between 4-6 months of age, not before 4 months and not after 6 months 1, 5
• When introducing potentially allergenic foods, do so one at a time with 2-3 days between new foods 5
• Iron-rich foods should be prioritized when starting complementary feeding 5

Recognizing and Managing Acute Reactions:

For mild reactions (1-2 episodes of vomiting, mild lethargy):

• Attempt oral rehydration at home

For moderate-to-severe reactions (>3 episodes of vomiting, moderate-to-severe lethargy):

• Seek immediate medical attention 1

CMPA management requires careful dietary management, regular monitoring, and appropriate formula selection to ensure optimal nutrition and growth while minimizing allergic symptoms.