Prather Pediatric and Allergy Center - Ask Doctor Brent

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Title: Can We Prevent Allergies?

Category: Asthma and Allergy


At the recent American Academy of Pediatrics convention a plenary talk was shared by Dr. Laurie Smith, a pediatric allergist from the National Institute of Health on the inheritance of allergies and preventive strategies. She reviewed the very important link with inheritance and allergies. If neither parent has allergies then less than 20% of their children will have allergies. If one parent has allergies there is a 50/50 chance that any given child will have allergies. If both parents have allergies there is about a 75% chance that each child will have allergies. Another way of predicting allergy in infants is to measure the umbilical cord blood IGE. If it is greater than 1.9 I.U. it's a very high risk factor for allergy, with about a 95% specificity.

Can breast feeding affect and prevent allergies? There have been numerous studies with confusing and conflicting results on this issue. Certainly, breast feeding is recommended by all pediatricians and allergists and is a way of at least delaying allergies such as asthma, hayfever, and eczema. Most of the research suggests that it can actually prevent certain types of allergies, specifically eczema. Eczema can be significantly decreased in high risk patients, down to 20%, if the mother modifies her diet and breastfeeds for an extended period of time. She must limit intake of high risk allergy foods in her diet while breastfeeding such as milk, eggs, nuts, seafood and also soy products. Is this a reasonable thing to ask a breastfeeding mother to do? I think it is, if she knows that the risk of her new baby is high. In other words, if a previous child born to her may have severe allergies and eczema already. She may have a sister or brother who's children have severe allergies. She or her husband may have had severe allergies in their lifetime. For all these reasons and a concern of high probability that the new baby will develop these allergies, I think it is worth going the extra mile with dietary control, prolonged breastfeeding and other environmental control measures such as minimizing dust, smoke, mold, animal hair and pollens in the home environment. It is also recommended to delay the onset of solid foods in these infants and delay introducing milk, soy, and wheat until 12 months and to delay exposure to ingestion of peanuts, other nuts and fish and shellfish to 36 months.

Numerous studies are now showing a very strong link with exposure to allergens in the home and development of allergies. This is especially strong for dust mite, passive smoke, and animal hair. We should try to control all these factors if at all possible in all children but most especially in high risk children. Most studies show that the risk of wheezing is increased four times if there is a smoker in the home. Another important avoidance measure to consider in a highly allergic young child is avoidance of day care. We now know that after several years of day care exposure, that it at least doubles the frequency of infections which complicate the child's allergies and asthma. It would be best if these high risk children could be cared for in a setting with as few other small children as possible.