Misconceptions about allergies are rampant, and below I discuss some of the most outrageous:
MYTH: SOME PETS MAY BE “HYPO-ALLERGENIC”
FACT: Unfortunately, our dogs and cats are a common source of allergies; however, none are free of these problems, despite much advertising to the contrary. Approximately 10 to 15 percent of the population suffers from pet allergies. The allergen is a specific protein produced not in the animal’s fur, but primarily in its skin and – a lesser extent- urine and saliva. As the animal is petted or brushed, or as it rubs up against furniture or people, microscopic flakes of skin (called dander) become airborne. Since all cats and dogs have skin, all are potentially allergenic. There’s a lot of false advertising by companies marketing supposedly hypo-allergenic pets, some selling cats or dogs for as much as $7,000 or more. While some of these animals have been bred to produce fewer major allergens from their saliva, sebaceous glands, or other glands, they still produce allergens that cause unpleasant symptoms in sensitized people.
Since short-haired pets have less hair to shed, they send less dander into the air, so are probably preferable for those with pet allergies. Dogs are half as likely to cause allergic reactions as cats, but if you’re allergic to furry animals, the only no-risk pets are fish and reptiles.
MYTH: ALLERGIES ARE PSYCHOSOMATIC
FACT: Allergies are very real – in some cases, potentially life-threatening, rooted in heredity and the environment; yet the mind plays a significant role in their behavior. Mental stress can precipitate or enhance allergic reactions, and relaxation techniques can moderate them. A person who is strongly allergic to roses, for example, may react to the sight of a plastic rose, demonstrating the involvement of the mind and the brain, but this relationship is not well understood.
MYTH: BLOOD TESTING IS A GOOD WAY TO DETECT ALLERGIES
FACT: Allergen-specific serum testing (for IgE) is not a reliable screen for allergy, and often leads to misinterpretation and false-positive results – which in turn lead to diagnostic confusion and unnecessarily eliminating foods from a diet. A negative test provides more useful evidence against such an allergy, but it also is not failsafe.
MYTH: SKIN TESTING FOR ALLERGY IS UNRELIABLE
FACT: The idea that skin testing is unreliable until 2, 3, or 5 years of age is sheer myth, but an ongoing one. Most evidence indicates that skin testing is reliable at any age.
A positive result, i.e., red, raised area called a wheal, means you reacted to a substance in a potentially allergic way. Such a positive result means the symptoms you are having are likely due to exposure to that substance. In general, the stronger the response, the greater chance of allergy to that given substance.
Skin tests are usually accurate, although people can have a positive response to skin testing without any problems with that given substance in everyday life. On the other hand, if the dose of allergen applied to the skin is large, a positive reaction may occur in people who are not allergic. A negative test result means there were no skin changes in response to the allergen, and that usually means that you are not allergic to that substance. Rarely, however, a person may have a negative skin test and still be allergic to the substance. In general, allergy skin tests are most reliable for diagnosing allergies to airborne substances, such as pollen, pet dander and dust mites. Skin testing may help diagnose food allergies. But because food allergies can be complex, you may need additional tests or procedures.
Your health care provider will consider your symptoms, considering the results of your skin test, to suggest lifestyle changes you can make to avoid substances that may be causing your symptoms.
MYTH: NO MILK, EGGS, OR NUTS FOR BABIES
FACT: Changes in recommendations over the years have contributed to the myth that highly allergenic food such as milk, eggs, or nuts should be avoided by infants until ages 1, 2, or 3 years. The most current recommendations from the American Academy of Pediatrics say that there’s no evidence to support avoiding highly allergenic foods past 4-6 months of age. Some evidence is emerging from recent trials that early introduction of highly allergenic foods may even promote tolerance, but if a baby’s sibling has a peanut allergy blood testing (IgE) before peanut introduction might be useful to provide evidence that this allergy is unlikely.
MYTH: CHILDREN OUTGROW ALLERGIES
FACT: Unfortunately, although children are ten times more likely than adults to have food allergies, many children may outgrow food allergies only to develop others. Some researchers believe that as a person’s gastrointestinal system develops, it gets better at blocking the absorption of components that trigger food allergies. Over time, children typically outgrow allergies to cow’s milk, eggs, wheat, and soybean products. Allergies to peanuts, tree nuts, fish, and shellfish, however, are more likely to be lifelong. And some children will outgrow one allergy only to develop another.
MYTH: WEARING GLOVES WILL PROTECT YOU FROM POISON IVY
FACT: “Leaves of three, let them be,” runs the standard advice on how to avoid poison ivy and its equally villainous cousins, poison oak and poison sumac. But those who are allergic to this relative of the cashew—as many as 85 percent of all Americans—find that no amount of armor or vigilance can protect them. The chemical that gives these plants their poisonous reputation is an oily resin called urushiol. And what makes it truly diabolical is that it can hitchhike on clothing, dog’s fur, and even garden tools. If you come into contact with poison ivy, wash the oil off (preferably with brown soap and water) within 20 to 30 minutes, before it soaks into the skin. Since the residue can remain potent for a year or more, scrub tainted items as well.
MYTH: ALLERGIES AREN’T LIFE-THREATENING
FACT: Although it rarely happens, allergies can kill. Some people have such an extreme sensitivity to a particular substance that the allergen can trigger an episode known as anaphylactic shock, a sudden, potentially fatal reaction that lowers blood pressure, swells the tongue, throat, or airways to the lungs, making it difficult to breathe. Such a reaction requires immediate medical attention. Anaphylactic shock is most often triggered by a food or drug, but it can also result from an insect sting or injections of various medical agents. People with a history of severe allergic reactions should always carry a pre-loaded syringe of epinephrine (adrenaline), which can be administered in an emergency.
MYTH: MANY PEOPLE ARE ALLERGIC TO MILK
FACT: When adults react adversely to milk – from cramps, gas, and diarrhea – symptoms are often mistaken for an allergic reaction. This is actually a condition known as lactose intolerance – an inherited trait caused by the body’s lack of an enzyme, lactase, needed to break down lactose, the sugar in milk or milk products. In cases of lactose intolerance, adults may use supplemental lactace—e.g., Lactaid —or consume dairy products from which lactose has been removed.
True milk allergy is only common among infants but is usually outgrown in adulthood.
MYTH: PEOPLE WHO ARE ALLERGIC TO SHELLFISH ARE ACTUALLY ALLERGIC TO THE IODINE
FACT: Some people who are allergic to seafood avoid certain skin medications and iodine-containing medical test substances because they fear an allergic reaction. But there is no connection between allergies to fish and shellfish and allergies to iodine. Allergies to fish and shellfish are caused by the protein within these meats and not to iodine, which is not an allergen. Surveys suggest that a majority of radiologists and cardiologists routinely ask patients about shellfish allergy before administering contrast media containing iodine (agents used to demonstrate pictures on X-rays). 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 agents, but this has nothing to do with iodine.
MYTH: NATURAL (“ORGANIC”) FOODS ARE NON-ALLERGENIC
FACT: Limiting your diet to organic food is no guarantee that you’ll avoid food allergies. In fact, some of the most allergenic foods are “natural,” unprocessed foods: cow’s milk, eggs, peanuts, wheat, soybeans, fish and shellfish and tree nuts. Combined, these foods account for up to 90 percent of all ingested allergic reactions. Allergies are caused not by chemicals related to growing the food, but by proteins in the food.
MYTH: ALLERGY SHOTS DON’T WORK
FACT: While immunotherapy given by injections may not work for all allergies and all people, it has been shown to be effective for allergies to insect venom 98 percent of the time, and for hay fever about 85 percent of the time. In some cases, immunotherapy can actually trigger an acute allergic reaction, but if the therapy is properly administered, these risks are minimal.
MYTH: ARTIFICIAL DYE CAN BE A COMMON SOURCE OF ALLERGY
FACT: Despite controversy around artificial food coloring since the 1950s and around food additives in the 1970s, there is no scientific evidence to support a link between exposure to artificial dye or coloring and allergic reactions. Rare cases of anaphylaxis have been reported in reaction to carmine, a natural red coloring derived from dried insects that is commonly used in cosmetics, but not in reaction to artificial dye.
MYTH: EGG IN VACCINES IS A FREQUENT CAUSE OF ALLERGY
FACT: The common MMR vaccine (measles, mumps and pertussis) is safe for anyone with a history of egg allergy, with no testing or allergy referral required. Influenza vaccine also generally can be given safely to egg-allergic patients, as concluded from dozens of trials. In this latter case, the Joint Council of Allergy, Asthma, and Immunology says there’s no need for a waiting period or referral to an allergy specialist, while the Centers for Disease Control and Prevention and the American Academy of Pediatrics recommend 30 minutes of observation for egg- allergic patients who receive influenza vaccine and referral to an allergist if there’s a history of anaphylaxis to egg. Egg-free influenza vaccine is a relatively new alternative.
Vaccine for yellow fever or rabies is contraindicated in patients with allergy to egg, but there are tests and procedures that may allow administration of these vaccinations in a graded manner in some patients. Egg-free versions of rabies vaccine also are an alternative. Gelatin in both of these vaccines can cause allergic reactions, so one must identify gelatin-hypersensitive patients before vaccinating.
MYTH: MOVING TO THE SOUTHWESTERN STATES WILL CURE ALLERGIES
FACT: For allergy sufferers, there is simply no safe haven. While desert regions have no maple trees or ragweed, they do have plenty of other plants that produce pollen, including sagebrush and cottonwood, ash, and olive trees. Relocating to such a region may offer relief for a few months, but a fresh crop of allergies to local plants is likely to develop before long.
MYTH: PENICILLIN ALLERGY IS COMMON
FACT: 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. Labeling someone allergic to this antibiotic makes them more likely to receive less-effective, more-toxic, costlier antibiotic alternatives. Thus efforts should be made to clear patients from retaining this label, if falsely applied.
MYTH: GLUTEN IS A COMMON SOURCE OF ALLERGY
FACT: Eating gluten is currently being blamed for many ails of humanity, largely driven by companies with products to sell—so you should avoid self-diagnosing gluten allergy. True hypersensitivity reactions can occur toward wheat, rye, or barley, but generally not to gluten. Celiac disease is an autoimmune condition (not traditional hypersensitivity) that improves with a gluten-free diet. Allergic type hypersensitivity to gluten is very uncommon, but patients more commonly report having “gluten sensitivity” and intestinal symptoms after eating foods with gluten. That’s a poorly defined condition that’s hard to prove. We have discussed this in a previous post (July 7, 2014).
MYTH: MOLD IS A COMMON SOURCE OF ALLERGY
FACT: Mold is everywhere and can cause real problems in susceptible persons, but rarely unless ingested in large quantities. Most health problems attributed to mold exposure are exaggerated, with no scientific basis or supportive evidence. But “hysteria” around mold has been a boon to some lawyers and companies that sell air purifiers and other detoxification equipment. So don’t get caught up in this hysteria.
This is a compilation of the most common myths about allergy. Hopefully this can provide you with some reassurance!