Physicians who believe they are seeing more allergies in pediatric populations are right. Comparisons of specific IgE (sIgE) antibodies between parents and the children in England and Kansas show a significant increase in sIgE in the younger generation.
    "If you ask about allergies among children today at a PTA meeting, 100% of parents will raise their hands," said P. Brock William, PhD, clinical professor of allergy immunology at Children's Mercy Hospital in Kansas City, Kan. "Now there is objective evidence that these kids are making a lot more sIgE than their parents."
    Allergic symptoms already affect between 20% and 30% of the U.S. population, Dr. William reminded the American Academy of Family Physicians Scientific Assembly, meeting in San Francisco. Symptoms generate 16.7 million physician office visits annually and cost some $15 billion dollars.
    "Left untreated, allergies can lead to significant complications in later life," Dr. Williams noted. "It is vitally important to find out what is going on."
    Recent reports indicate that the incidence of allergies has increased significantly with the current cohort of children, Dr. William noted; he maintained that most such reports are subjective. Studies typically leave unanswered questions about better recognition of allergic symptoms; the greater numbers of children being tested today; and changes in the perception of allergic reactions. The CMH group tried to begin answering those questions.
    Researchers compared antibodies to dust mites, cat, and Alternaria mold among 677 parents with reversible airway disease and their 804 offspring. There is a direct correlation between sIgE antibody levels and the severity of allergic symptoms. If sIgE levels were higher in the children than in their parents, the children would be expected to exhibit more severe symptoms.
    The result is clear, Dr. William said. When tested for dust mite antibodies, the average parent had an sIgE level of 14.6 kilounits of allergen per liter (kUA/L). The average for offspring was 50.2 kUA/L. Only 10% of parents had mite-specific IgE levels about 100 kUA/L, but 42% of their offspring topped the 100 mark. Serum levels of sIgE for cat and Alternaria antibodies were similarly elevated, but the absolute levels were lower.
    Why children exhibit such high levels of sIgE antibodies is not known, Dr. William said. External factors could include increases in atmospheric pollution as well as indoor climate changes due to more carpeting, higher humidity from air conditioning, and similar factors.
    Internal factors might include changes in hygiene and antibiotic use, a greater incidence of rhinovirus and other viral infections, increases in vaccination and medication use, or changes in diet and exercise leading to increased obesity in children. Medication could be an important factor, Dr. William noted, since use of albuterol and other bronchodilators ease breathing and enable children to inhale more allergens.
    "We are grasping at straws here," he admitted. People are even suggesting global weather changes producing more pollen. We don't really have a clue as to why sIgE is up, but we have objective evidence that it is happening."