LW: How can you tell who will outgrow an allergy?
DR.: Up until recently, determining if a child might lose a food allergy was a trial-and-error process. Doctors would do skin testing to get clues but ultimately it would come down to an oral challenge. The child would eat a bit of the offending food and if there was no reaction, it was assumed the allergy was outgrown. It's important to note that a child with anaphylaxis is not challenged until laboratories or repeat skin testing clarifies the situation. Controlled and observed food challenges are ultimately the gold standard in judging if someone has a food allergy.
Recently, several studies suggest that doctors can use blood work, specifically RAST testing, to identify and track the child who will outgrow the condition. Researchers led by Hugh A. Sampson, M.D., and Scott Sicherer, M.D., at Mt. Sinai School of Medicine in New York and Robert Wood, M.D., at Johns Hopkins suggest that children whose RAST values decrease by over 50 percent within a given time period are more likely to pass an oral challenge to egg or milk. The same idea can apply to peanut and tree nut allergies. This system isn't perfect, but doctors can now advise parents about the best time to consider an oral challenge and the likelihood that a particular food allergy will be outgrown.
LW: Can parents do anything to increase the odds?
DR.: For a child with a true food allergy, strict avoidance of the allergen is the only means to help him or her outgrow it. Between the ages of two to five years, a child's immune system is still malleable and maturing. By avoidance, doctors hope to trick the immune system into forgetting that a certain food like egg, for example, is a bad thing. We're basically waiting for memory cells to either forget or die off. This is the same logic behind the use of vaccines and booster shots. For those kids with very mild allergic reactions, strict avoidance may seem like overkill. Until doctors can conclusively identify which youngster will always have a mild reaction for example, the child who can't eat an egg but can eat baked goods that contain eggs doctors will tend to be conservative and advise avoidance.
LW: Are there any new treatments on the horizon for food allergies?
DR.: There are several studies examining probiotic supplements and their influence on the developing immune system, but we have a long way to go before doctors have good information to help families. Researchers are also looking at ways of desensitizing children or people with food allergies by using certain genetically modified foods -- for example, peanuts with a lower allergenic profile. This approach is several years away from being used as human treatment.
LW: What advice would you give parents to help families get through the holidays safely?
DR.: This season is always a challenging time for allergic families. Not only are many risky foods readily available, but the chaos of travel, holiday get-togethers, and dealing with family dynamics can be difficult. The holidays are stressful in their own way for everyone. Allergic families have the added stress of celebrating with food and having to make amends and explanations because a loved one can't ingest items commonly associated with ethnic or family traditions. Families have to balance safety with having the child feel comfortable and a part of the celebration.
Very often, this is the time of year when a parent has to confront family members who aren't vigilant or concerned enough about a dietary issue. This is often when mistakes happen or assumptions are made. Parents should be prepared to discuss the allergy issue early and be ready to stand firm on whatever decisions are appropriate for their child. I remind parents that they are their child's best advocates and sometimes hard decisions have to be made. Baked goods are usually the biggest offenders at the holidays so parents should watch out for them. Monitoring for accidental ingestion is a real concern. Watch out for things like bowls of nuts sitting out. I give the parents of allergic kids the same advice I would give to parents of toddlers. Sometimes you just have to go into a house and baby proof it. When staying away from home, parents should know the location of the nearest emergency room. In addition, they should always carry an epi-pen and be prepared to use it. Many people aren't comfortable using these pens, but Benadryl and other antihistamines are not a cure for anaphylaxis -- they only buy time or make skin symptoms better. Reminding everyone of how quickly a child can get sick is important and having a standard plan of action is always advisable.
Pediatric allergist Harvey L. Leo, M.D., holds an academic position at the University of Michigan School of Public Health and works at Allergy and Immunology Associates in Ann Arbor, Michigan. |
