Cow’s Milk Protein Allergy (CMPA)

Introduction

• Breast milk contains fats, carbohydrates (lactose), and maternal diet-derived proteins (whey, casein).
• Whey and casein proteins are found both in breastmilk, cow’s milk, and soy-based formula.
• Food protein induced allergic proctocolitis or Cow’s Milk Protein Allergy (CMPA) refers to adverse allergic reactions to proteins found in cow's milk, leading to rectal and colonic inflammation.

Epidemiology

• Cow protein Milk Allergy affects approximately 2-3% of infants.
• Cow milk-protein allergy is a condition exclusive to infants, almost all cases are diagnosed before the age of 1 year.

Types

Important Note: There’s a third mechanism, known as mixed type Cow’s Protein Milk allergy, with manifestations involving inflammation of the esophagus.

Clinical Picture

• Symptoms:
  • Skin: Eczematous rash and hives.
  • Gastrointestinal: regurgitation, vomiting, diarrhea, abdominal pain, colic, and/or painless bloody stools.
  • Respiratory: nasal congestion, wheezing, difficulty breathing (more common in IgE-mediated cases).

Diagnosis

• The diagnosis is mostly clinical and confirmed when symptoms improve in response to dietary modifications.
• Other tests that can be done to support the diagnosis, including:
  1. Skin Prick Test: Identifies IgE-mediated reactions.
  2. Serum Specific IgE Testing: Measures IgE antibodies to cow's milk proteins.
  3. Elimination Diet: Removal of cow's milk from the diet and monitoring for symptom improvement (for at least 2 weeks)

Treatment

1. Elimination of Cow's Milk
   • Avoid all forms of cow's milk and products containing cow's milk protein.
   • Due to cross-reactivity, both dairy and soy should be avoided.
   • The mother of a breastfed infant can breastfeed after eliminating dairy and soy products from her diet.
2. Switching Formulas
   • Use hypoallergenic formulas (e.g., extensively hydrolyzed formulas), they contain predigested proteins that do not induce an allergic reaction.
   • if there is no response to hydrolyzed formulas, we switch to amino acid-based formulas.

Prognosis

• Visible bleeding should resolve within 3 days of diet elimination, but complete resolution may take up to 2 weeks.
• Almost all infants can tolerate dairy and soy products by age 1 year.
• Many children outgrow CMPA by age of 3-5 years.