What are the diagnosis and treatment options for cow milk protein allergy?

Diagnosis and Treatment of Cow's Milk Protein Allergy

Cow's milk protein allergy (CMPA) should be diagnosed through a structured approach using elimination diet followed by challenge testing, with management based on the severity and type of reaction (IgE vs non-IgE mediated). 1

Diagnosis Algorithm

Clinical Presentation

• IgE-mediated reactions (immediate, within minutes to 2 hours):

  • Urticaria, angioedema, erythema
  • Vomiting, diarrhea, abdominal pain
  • Wheezing, rhinitis, coughing
  • Hypotension (in severe cases) 1

• Non-IgE-mediated reactions (delayed, 2-72 hours):

  • Persistent diarrhea, vomiting, blood in stool
  • Failure to thrive
  • Atopic dermatitis, eczema
  • Irritability, feeding difficulties, sleep disturbance 1

Diagnostic Steps

1. Detailed clinical history and physical examination:

   • Document timing, consistency, and severity of symptoms in relation to milk consumption 1

2. Testing based on suspected mechanism:

   • For IgE-mediated CMPA: Skin prick test and serum-specific IgE testing
     • Note: Positive tests indicate sensitization, not necessarily allergy 1
   • For non-IgE-mediated CMPA: Elimination diet is primary diagnostic tool 1

3. Elimination-Challenge Protocol:

   • Eliminate cow's milk protein for:
     • 2-4 weeks in IgE-mediated cases
     • 2-6 weeks in non-IgE-mediated cases 1
   • If symptoms resolve during elimination, proceed to challenge

4. Oral Food Challenge (OFC):

   • Gold standard is double-blind placebo-controlled food challenge (DBPCFC)
   • In clinical practice, open challenges are more commonly used 1, 2
   • Challenge should be performed in a medical setting, especially for IgE-mediated reactions 3

Special Considerations

• For Food Protein-Induced Enterocolitis Syndrome (FPIES), a severe systemic response:

  • When history is compelling (≥2 reactions with classic symptoms to same food within 6 months)
  • Elimination of symptoms when food is removed
  • Oral food challenge may not be necessary initially 3

• For Allergic Proctocolitis (AP):

  • Presents as mucoid, blood-streaked stools in otherwise healthy infant
  • Can also manifest as chronic emesis, diarrhea, and failure to thrive 3

Treatment Algorithm

First-Line Management

1. For breastfed infants:

   • Continue breastfeeding with maternal elimination diet
   • Consider calcium and vitamin D supplements for the mother
   • Monitor infant's growth and symptoms 1

2. For formula-fed infants:

   • First choice: Extensively hydrolyzed formula (eHF) of cow's milk protein
     • Tolerated by >90% of children with CMPA 1, 4

3. If symptoms persist with eHF:

   • Second choice: Amino acid formula (AAF) 1, 4, 5

4. Alternative options (based on availability and tolerance):

   • Rice protein-based extensively hydrolyzed formula (rHF) can be an alternative to CMP-based eHF 4, 5
   • Soy protein-based infant formulas for infants >6 months, after establishing tolerance to soy protein 4, 6

Medication Management

• Antihistamines for mild-moderate IgE-mediated reactions 1
• Epinephrine auto-injector for severe reactions with training on its use 1

Nutritional Management

• Ensure adequate calcium intake
• Monitor growth and development
• Consider referral to pediatric dietitian 1

Follow-up and Monitoring

Reassessment Schedule

• Review within 2-4 weeks after starting elimination diet
• Regular monitoring of growth parameters
• Reassessment for tolerance development:
  • Every 6-12 months for children under 2 years
  • Every 12-18 months for older children 1

Reintroduction

• Oral food challenge at 9-12 months to assess tolerance development 4
• CMPA usually resolves during first 2-3 years of life 4
• IgE-mediated CMPA tends to be more persistent than non-IgE-mediated 4

Common Pitfalls to Avoid

• Overdiagnosis and unnecessary dietary restrictions
• Delayed diagnosis leading to malnutrition
• Inappropriate formula choice
• Inadequate parent education 1, 7

Indications for Specialist Referral

• Anaphylaxis
• Failure to thrive
• Multiple food allergies
• Significant feeding difficulties
• Persistent symptoms despite appropriate elimination diet
• Diagnostic uncertainty
• Parental anxiety 1

By following this structured approach to diagnosis and treatment, clinicians can effectively manage CMPA while minimizing unnecessary dietary restrictions and ensuring optimal nutrition and growth for affected infants.