乌鸦传媒

BALTIMORE -- Egg allergy is no issue for flu vaccination, allergen avoidance isn't a cure for eczema, and testing tots doesn't make skin prick testing any less accurate, according to allergists taking aim at common misconceptions.

"These myths and misperceptions are coming to us not only from our patients, but we're having patients referred to us from the primary care physician due to some of these as well," , of Nationwide Children's Hospital in Columbus, Ohio, explained in an interview.

He and colleague , of Ohio State University, also in Columbus, expounded on the top 10 offenders at a myth-busting workshop at the American College of Allergy, Asthma, and Immunology meeting.

At the top of that list for this time of year was egg allergy and vaccinations.

Vaccines against influenza and measles, mumps, and rubella (MMR) as well as some others are prepared with chicken egg embryo cultures or fluids such that one-trillionth or one-millionth of a gram of egg protein can make it into the shot.

But more than 25 trials and guidelines have shown that the flu vaccine is safe for egg-allergic children, likely even for those with a history of anaphylaxis to egg.

The Flublok recombinant vaccine approved this year is another option without any egg protein or live virus.

The CDC still recommends allergist referral for kids that have anaphylaxed to egg in the past but says go ahead and vaccinate all the rest.

MMR vaccination doesn't require an egg allergy skin test beforehand and is safe with any history of egg allergy without referral to an allergist, Stukus and Martin pointed out.

But many pediatricians and primary care physicians aren't comfortable with that yet and are either withholding vaccine or referring out when not necessary, which delays administration and leaves kids at risk, Stukus told 乌鸦传媒.

Adverse vaccine reactions that do occur aren't always due to immunologic reactions, and those that are could be due to gelatin or other components, they added.

Underlying most of the misperceptions is a faulty definition of "allergy," leading to frequent diagnoses without a true immunologic or immediate hypersensitivity reaction, Stukus noted.

"If you have an allergy to something you should have immediate-onset, reproducible symptoms every time you encounter whatever it is -- food or medication," he said.

Sensitivity or intolerance can cause more delayed symptoms but are separate issues, Stukus noted.

That's the case for more than 90% of people labeled as allergic to penicillin, who have delayed-onset reactions like hives rather than true immediate hypersensitivity reactions, he pointed out.

"Once people have a label of having penicillin allergy on their chart, then they will often receive other antibiotics that may not be indicated for their condition, that may cost more, or that may not be as effective," he told 乌鸦传媒. "Be thoughtful about diagnosis of allergy."

Those patients for whom penicillin is avoided don't have to avoid the whole class, either, he emphasized, pointing to lack of cross-reactivity with third and fourth generation cephalosporins.

Gluten allergy, while a hot topic, suffers the same lack of popular distinction between true allergy (celiac disease), non-celiac gluten sensitivity (for which there is no objective sign, symptom, or test), and immediate hypersensitivity to bread and pasta due to wheat itself -- not gluten.

There are also a lot of misconceptions about the age at which allergy testing is reliable, Stukus noted.

Many pediatricians even think that skin and serum testing has to wait until 2, 3, or 4 years of age, whereas it's reliable as early as 3 months, he explained.

Both tests have a high negative-predictive value, so if they turn up negative, don't blame it on the child's age, Stukus said.

A positive test result, on its own, doesn't indicate allergy at any age in the absence of symptoms. It's not a reliable screening test, Stukus and Martin emphasized.

Another common myth that leads to referral is that the allergist will "find out what's causing eczema." However, allergy is only a contributing factor for about one-third of kids with severe cases or eczema, and few with mild or moderate disease.

"For patients with severe refractory eczema that really are doing all the right things, it can be useful to determine if an allergy is contributing," Stukus said. "However, we still won't find a sole cause and we cannot offer a cure for eczema."

Other popular myths discussed at the session are asking about shellfish allergy before giving radiocontrast media ("there's no relationship whatsoever"), dye and artificial food coloring allergy ("there's no compelling evidence ... stop the madness!"), so-called hypoallergenic cats and dogs ("It's not the hair that causes allergy!"), and testing for mold exposure.

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