A child is more likely to develop this kind of allergy if blood relatives also experience allergies, such as eczema, asthma or hay fever.Fortunately, approx 1/2 of the???children affected by a milk allergy will outgrow the problem by 1 to 2 years of age, and approximately???3/4???of children will have outgrown it by the time they are 3 or 4 years old.