From the Guidelines
Milk protein allergy is typically diagnosed in infants during the first year of life, with most cases identified between 2 and 3 months of age. The condition often presents shortly after formula or cow's milk is introduced into an infant's diet, though breastfed babies can also develop symptoms if the mother consumes dairy products. According to the most recent study 1, early introduction of allergens in infants, such as the introduction of peanut or egg beginning at age 4 to 6 months, prevents the development of food allergy, and for milk, the window of opportunity is probably much earlier. Diagnosis usually occurs when parents notice symptoms such as skin rashes, vomiting, diarrhea, blood in stool, excessive crying, or poor weight gain after milk consumption. Healthcare providers diagnose the condition through a combination of medical history, physical examination, elimination diets, and sometimes specialized allergy testing.
The introduction of solid foods, including potentially allergenic foods like dairy, should not be delayed beyond 4 to 6 months, as recommended by the US National Institute of Allergy and Infectious Diseases Guidelines 1. Most children (approximately 80-90%) outgrow milk protein allergy by age 3-5 years, with many showing improvement by their first birthday. Early diagnosis is important for proper management, which typically involves eliminating cow's milk proteins from the diet and substituting with appropriate hypoallergenic formulas such as extensively hydrolyzed or amino acid-based formulas for formula-fed infants, or maternal dairy elimination for breastfed babies. Key considerations for diagnosis and management include:
- Medical history and physical examination
- Elimination diets
- Specialized allergy testing
- Introduction of solid foods, including potentially allergenic foods, at the appropriate age
- Maternal diet and lactation practices, as restriction of maternal diet during pregnancy or lactation is not recommended as a strategy for preventing the development of food allergy 1.
From the Research
Diagnosis of Milk Protein Allergy
- Milk protein allergy is typically diagnosed in infancy, with most infants developing symptoms before one month of age, often within one week after introduction of cow's milk-based formula 2.
- The median age of onset of milk protein allergy symptoms can range from 6 to 10 weeks 3.
- In premature infants, there is typically a significant delay in the onset of milk allergy compared to full-term infants, but rare cases of early onset have been reported 4.
- Most children with cow's milk protein allergy present with symptoms at an age of less than 1 year 5.
Symptoms and Diagnosis
- Symptoms suggestive of milk protein allergy may be encountered in about 5-15% of infants, emphasizing the importance of controlled elimination and milk challenge procedures 2.
- The diagnosis of milk protein allergy is based on strict well-defined elimination and milk challenge procedures, as no single laboratory test is diagnostic of milk protein allergy 2.
- Diagnosis is suspected on history alone, with laboratory evaluations playing a supporting role, and confirmation requires elimination and reintroduction of the suspected allergen 6.