This month, Dr. Sydney Spiesel discusses peanut allergies, the stubbornness of dust mites, how breast-feeding may help prevent diabetes, and the fallout from a toxic spill in China. (Click here and here for the last two roundups.)
Kissing: Peanut alert.
State of the Science: Between 6 percent and 12 percent of people who are intensely allergic to peanuts report that they've had a reaction after kissing someone who has eaten peanuts as many as six hours beforehand. Usually, the result is skin irritation, blistering, or swollen lips. But this week, a 15-year-old Canadian youngster with a peanut allergy died after kissing her boyfriend, who had just eaten a peanut-butter sandwich. She collapsed as a result of anaphylactic shock, the most intense form of allergic reaction. Appropriate treatment with injected epinephrine failed to save her.
Prognosis: It's estimated that about 100 peanut-allergic people die annually in the United States after accidental exposure. The mechanism of peanut allergies is similar to that of other allergies, but the effects tend to be worse. And peanut allergies are less likely to fade with time than most other food allergies. The fuss over peanuts is justified. Here are steps we should take to prevent sad accidents:
- Restaurants should never use peanut butter as a "secret ingredient" and should probably indicate the presence of peanut- or tree-nut-containing foods on their menus.
- Schools need to think out policies that restrict or forbid peanut products in the lunchroom. School nurses should be trained and prepared to deal with life-threatening allergic reactions.
- Seriously allergic children should be trained about how to avoid risk. They should also at all times carry epinephrine autoinjectors (EpiPen is the major brand for this product) and an antihistamine like Benadryl. Both should be taken at the first inkling of exposure. Most patients should not wait to see if the treatment is effective because if it isn't working, they will be in big trouble. Instead, a fast trip to the emergency room is in order.
- Oh, and significant others shouldn't munch on peanuts or their products for several hours before they kiss their allergic good friends.
Dust Mites: Why we're stuck with them.
More allergens: If you are allergic to anything at all, you are probably also allergic to cats, dust, or both. I don't mean cats themselves or even their dander (shed flakes of dead skin). I mean cat spit. As you've probably noticed, cats constantly lick themselves. Many humans—perhaps most—are intensely allergic to a saliva protein that dries on the cat's fur. We inhale microscopic particles of this protein, and it makes us wheeze.
The most significant allergen in dust comes from the bodies and droppings of dust mites. These mites are microscopic creatures, similar to insects but more closely related to spiders (they have eight legs instead of six and don't fly). They're too tiny to see unless they are floating in air and illuminated by a bright light against a dark background. They live in fibers, preferring the natural to the synthetic. They mainly subsist on the tiny flakes of skin that are constantly falling off us—their Latin name means "skin eaters." Dust mites stimulate an asthma attack in many people when they're inhaled, after we've raised them into the air simply by walking on a carpet or dropping into bed.
The fight: It's not easy to get rid of mites. Conventional wisdom has recommended vacuuming them up with special (and expensive) HEPA vacuum cleaners. Ordinary vacuum cleaners suck up the mites but can't then strain out their minute bodies, so the mites that are vacuumed just blow back into the room. It turns out, however, that this is only a small piece of the problem. In a funny way, vacuuming—even HEPA vacuuming—actually causes the dust-mite problem.
State of the Science: A wonderful and long-neglected study by Dutch researcher D.P. Wassenaar, working in the Department of Dermatology of the University Hospital in Utrecht, tried to determine how much vacuuming it would take to clear dust mites out of carpets. Wassenaar filled a laboratory with carpets, which were frequently and repeatedly vacuumed with a powerful machine. Early on, no matter how much vacuuming was done, the daily mite yield remained pretty much constant. But as time went on, the yield went way, way up. How?