The prevalence of severe food allergies ranges from 10 percent in 2-year-olds and 7.1 percent in children between 14 and 17 to 10.8 percent in adults aged 18 and over. Although allergies to milk, eggs, wheat, and soy are often overcome in infants and young children, others in the Big 9 almost always persist for life. And whoever was allergy-free as a teenager doesn’t necessarily have to stay that way. New food allergies can arise at any age.
According to Dr. Scott H. Safe, allergist at the Icahn School of Medicine at Mount Sinai, New York, and co-authors: “Remarkably, about half of US adults with food allergies report developing at least one of their food allergies in adulthood, the shellfish allergy being for most of these cases is responsible. “
The only real food allergies are adverse immunological reactions, explained Dr. Safer. The body reacts to an otherwise harmless food like a life-threatening infection and starts a large-scale offensive. Symptoms can include hives, difficulty breathing, vomiting, or anaphylaxis – a severe, potentially fatal shock reaction that occurs within seconds or minutes of exposure to an allergen, sometimes in tiny amounts. For this reason, most airlines no longer offer passengers peanuts – just spraying peanut dust can be fatal for some people with peanut allergies.
More than 40 percent of food allergic children and half of food allergic adults will experience at least one severe reaction in their lifetime. Among those allergic to one or more of the Big 9 allergens, severe reaction rates exceed 27 percent, with peanut allergy topping the list at 59.2 percent in children and 67.8 percent in adults with peanut allergy.
However, many people who believe they have a food allergy don’t when tested with a blind oral challenge that involves testing foods under medical supervision to see if a child is responding, the gold standard for diagnosing Food allergies. Others mistakenly view all kinds of food side effects – from upset stomach to headaches – as allergies. Food intolerances, for example to lactose, the natural sugar in milk, are not an immune reaction, but result from a deficiency in the enzyme lactase. Many Asians develop redness and redness when consuming alcohol because they lack an enzyme to digest it. Other people may think they are allergic because they are experiencing drug-like reactions, such as being extremely nervous from the caffeine in coffee and tea.
Sometimes long-term avoidance of a food can lead to an allergic reaction when that food is eventually consumed. This can happen to children with skin allergies who avoid milk; they may experience an allergic reaction later when they finally consume it. Occupational exposure, the use of skin care products, even tick bites can sometimes lead to food allergies in adulthood if both are cross-reactive with an allergenic substance.
And while allergy-prone families have historically been advised not to expose their children to peanuts until the age of 3 (advice that likely contributed to the recent explosion in peanut allergies in children), it now appears that introducing it early – at 6 months – a highly allergenic food is actually protective and reduces the risk of a later reaction, said Dr. Safer.