Know the urban myths that compromise allergy care
AT 2014 AAAAI ANNUAL MEETING
• Shellfish, iodine, and radiocontrast media: Surveys suggest that a majority of radiologists and cardiologists routinely ask patients about shellfish allergy before administering iodinated contrast media, even though iodine is not an allergen, Dr. Stukus said. This myth seems to have originated from a 1975 study in which patients with any kind of reported allergy were twice as likely to react to contrast media (Am. J. Roentgenol. Radium. Ther. Nucl. Med. 1975;124:145-52). Reports of seafood allergy in 15% of patients were associated with reaction to contrast media, but so were reported egg, milk, or chocolate allergy, each in 15% of patients. "Have any of you ever asked patients if they have a chocolate allergy before irradiating them?" Dr. Stukus asked.
Reactions to radiocontrast media with high osmolality agents are common, however, affecting 5%-12% of patients, with elevated risk in patients with atopy. Premedication regimens for patients with a previous reaction to radiocontrast media can lower the risk to less than 1%.
• Skin testing: The idea that skin testing is unreliable until 2, 3, or 5 years of age is sheer myth, but an ongoing one. "I had one of my colleagues say this to me 2 weeks ago," Dr. Stukus said. Skin testing is reliable at any age and can accurately assess for the presence of specific IgE, he said.
• Penicillin allergy: Adverse reactions to antibiotics are very common, but true allergic reactions are uncommon. Approximately 10% of people in general say they are allergic to penicillin, but fewer than 10% of those will have a positive skin test or symptoms if challenged. "If patients get labeled allergic" to penicillin "on their chart, that follows them forever" and makes them more likely to use less-effective, more-toxic, costlier antibiotic alternatives, Dr. Stukus said. "We can improve their lives by proving they don’t have it and taking this label off their chart."
• Gluten: Eating gluten "is currently being blamed for the ails of humanity," largely driven by companies with products to sell – so be prepared to talk about this with patients with self-diagnosed gluten allergy, Dr. Stukus said. IgE-mediated hypersensitivity reactions can occur toward wheat, rye, or barley, but not to gluten. Celiac disease is an autoimmune condition (not IgE-mediated hypersensitivity) that improves with a gluten-free diet. IgE-mediated hypersensitivity to gluten is very uncommon, but patients more commonly report having "gluten sensitivity" and GI symptoms after eating foods with gluten. That’s a poorly defined condition that’s hard to prove. A double-blind, placebo-controlled challenge is the only available method of diagnosing gluten sensitivity.
• Mold: Mold is everywhere and can cause real disease in susceptible persons, but mycotoxins rarely cause disease unless ingested in large quantities. Most health problems attributed to mold exposure are exaggerated, with no scientific basis or supportive evidence, Dr. Stukus said. But "hysteria" around mold has been a boon to some lawyers and companies that sell air purifiers and other detoxification equipment. Know your approach to identifying mold allergy, and be straightforward with patients, he advised.
Dr. Stukus reported having no financial disclosures.
On Twitter @sherryboschert
