Peanut allergies

During dinner one night with Mom, Roy and Polly Ann we got into a rather heated debate about peanut allergies. Polly Ann recently took a flight to Florida and she had packed her own lunch - which included a peanut butter & jam sandwich. When she got on the plane, the flight attendants informed the passengers that there was a child on board with a severe peanut allergy and asked everyone to refrain from eating anything with peanuts. Polly Ann was rather frustrated at this and wondered why more kids have peanut allergies these days...

According to a recent survey in the US (Sicherer et al., 2003), the prevalence of nut allergies (including peanut) has increased in children from 0.6% in 1997 to 1.2% in 2002 and this was primarily due to an increase in the prevalence of peanut allergies (0.4% in 1997 to 0.8% in 2002). In addition to the genetic component, possible reasons for this increase include

• increased allerginicity of roasted forms of nuts
• early feeding when the immune system is immature
• use of topical ointments that contain peanuts
• use of soy formulas
• hygiene hypothesis: children who are around other children and animals early in life are exposed to more microbes and therefore their immune system builds up tolerance to irritants that cause allergies such as asthma. When the immune system lacks practice fighting bacteria and viruses, perhaps from an overly sanitary lifestyle, the other system becomes too powerful and overreacts -- as an allergic reaction -- to peanuts (and other allergens like pollen).