By Angela Pirisi
While springtime heralds flowers and warmth, for many it means the start of seasonal allergies, as an explosion of plant pollen in the air make us itch, sneeze and wheeze. Although seasonal allergies plague many adults and kids alike, they’re not the only kind to cause annoying symptoms. And some allergic reactions, such as to peanuts, can even be life-threatening. Luckily, experts are shedding more light on allergies, leading to a better understanding of what irks our immune systems, as well as how to prevent and treat various reactions. Here’s what you need to know.
Q: How do you get allergies?
A: An allergy happens when the body overreacts to an otherwise innocuous substance in our surroundings, whether it’s pollen, peanuts, pet dander or something else. Some people have hypersensitive immune systems that develop antibodies in response to ordinary exposure to various substances. “Allergy development goes through four stages,” explains Dr. Wade Watson, professor of pediatrics at Dalhousie University and head of the division of allergy at the IWK Health Centre in Halifax. First, a person is exposed by eating, touching or inhaling the allergenic substance, sensitizing the body, which produces immunoglobulin E (IgE) antibodies that sit on mast (allergic) cells in various parts of the body, ready to attack during the next exposure. When that happens, the body releases a chemical called histamine, which cause the allergic responses.
Q: What are the main types of allergies?
A: You can be allergic to something by touch (contact dermatitis), by inhaling it (airborne) or by ingesting it (food). You can be allergic to any number of things in your environment, some of which can cause symptoms that are simply irritating, such as sneezing, while others can be life-threatening, causing reactions strong enough to make your airways swell or your heart fail. “The only true difference among allergies is what parts of the body they affect and how severely our immune system responds,” says Ottawa-based Dr. Zave Chad, chair of the Canadian Pediatric Society’s
Q: what kinds of allergic reactions can you have?
A: That depends on the type of allergy and what part of the body is affected, explains Watson. Airborne allergens such as pollen or cat dander affect the nose, eyes and lungs. Food allergens, however, can affect the skin, mouth, respiratory system, GI tract and more. That’s because food allergens get into the bloodstream, so a full-body reaction is possible. Contact allergies (to things like nickel from costume jewelry) affect skin, causing eczema or hives occur.
Q: What is a seasonal allergy?
A: Seasonal allergies can be broken down into four different types, depending on the culprit in season: tree pollen, grass pollen, ragweed pollen or mold (mold is more problematic in damp weather). However, some people can also suffer from airborne allergies all year round, which makes them “perennial.” Most often, if allergy symptoms trail into fall and winter, it’s likely a mold allergy or indoor allergens such as dust mites.
Q: When are allergies most likely to show up?
A: Allergies can develop at any time in life, but most often eczema and food allergies appear during the first year of life, asthma crops up in the second year, allergic rhinitis (inhalant or pollen allergy) by age four to seven and medication allergies can present themselves at any time.
Q: What are the chances of developing an allergy?
A: While it’s not certain whether early life exposure to certain substances can heighten the risk of an allergy, family history is a known risk factor. Someone with no family history of allergy or asthma has a 15 per cent chance of developing an allergy; having one allergic parent results in a 30 per cent risk; and having two allergic parents adds up to a 45 per cent chance, says Watson. However, you won’t necessarily develop the same allergy.
Q: Do allergies ever go away or can you make them disappear?
A: It’s possible for some allergies to disappear at any point, while others are life-long. For example, a seasonal allergy generally persists through adulthood and tends to disappear when people are in their 60s or 70s. Generally, though, milk and egg allergies can subside by school age and peanut allergies by age five to 15 in up to 20 per cent of kids, explains Watson. But never test a food allergy yourself at home. If you suspect your child has outgrown his allergy, always consult an allergist, who will perform tests in a setting that can handle a medical emergency, since some reactions can be fatal if not treated urgently. (See “Anaphylaxis — when allergies can turn deadly”)
Q: Can you cause an allergy in your child by exposing him early on or even during pregnancy?
A: Not that we know for sure, say the experts. “Evidence doesn’t definitively show that anything you do or don’t do in the first six to 12 months of life alters the chances of developing certain allergies,” says Watson. Likewise, there’s no hard evidence that what you do in pregnancy can lead to allergies in your child. However, many doctors will still advise breastfeeding women to avoid or limit their intake of allergenic foods, such as peanuts, shellfish and dairy. What studies do show is that breastfeeding for four months or more reduces the chances of allergy in children.
And science hasn’t proven that avoiding allergens can prevent your child from becoming allergic either. There’s a debate around whether avoiding certain allergens in a child’s environment and diet prevents sensitization that would lead to allergic reactions or if exposure to allergens early in life can help build tolerance. Experts can’t yet suggest whether to buy a cat or get rid of the one you have. Chad says he errs on the side of caution, advising
parents to delay the introduction of certain allergenic foods to their children’s diets until age three.
Q: Can seasonal allergies lead to asthma or vice versa?
A: Research is making it more apparent that there’s a link between allergic rhinitis (seasonal allergy) and asthma, says Chad. In fact, 40 per cent of people with allergic rhinitis also have asthma (the risk is heightened if symptoms are poorly managed). For those who have both a pollen allergy and asthma, uncontrolled hayfever can exacerbate asthma symptoms and increase the need for medications. And poorly managed asthma raises the severity of an allergic reaction, including anaphylaxis, says Chad. Most kids at risk of anaphylaxis also have asthma. “Look at it this way: Allergy is the cause, and asthma is the effect,” explains Chad. “Whereas a pollen allergy causes inflammation of the upper airways [your nose and throat], asthma is allergy’s effect on the lower airways instead, namely your lungs.”
Q: What’s the difference between a food allergy and a food intolerance?
A: A food intolerance is an adverse reaction to food, which doesn’t involve the immune system. Lactose intolerance, for example, results when someone doesn’t have the enzyme needed to digest milk sugar, so gastrointestinal symptoms such as gas, bloating and cramping occur. When people have food allergies, their immune systems react to the food by pumping out IgE antibodies, which lead to the release of chemicals that can trigger anything from hives to broader anaphylactic reactions.
Q: What can we do around the house to keep allergens/dust mites under control?
A: First, identify your triggers before you start tearing up the broadloom and kicking out the cat, suggests Edmonton pediatric immunologist and allergist Dr. Timothy Vander Leek, a spokesperson for the Canadian Society of Allergy and Clinical Immunology (CSACI). There are many possible allergens or irritants in a home, such as mold or dust from inside, or pollen coming in the windows. Once you’ve been tested, you can make appropriate changes to your environment, such as encasing mattresses and pillows or putting filters on vents.
Q: Can you have an allergic reaction to food just by smelling or touching it, without eating it?
A: By far, the most threatening kind of exposure is direct ingestion of a food allergen, says Laurie Harada, the executive director of Anaphylaxis Canada. However, even a trace amount of a food allergen that gets transferred to a
utensil has the potential to cause a severe allergic reaction. For example, steam from cooked fish and seafood contains proteins that become airborne and, when inhaled, can trigger asthmatic reactions and even anaphylaxis in certain allergic individuals.
Q: What happens if you don’t treat allergy symptoms?
A: Fixing that leaky faucet on your kid is important, and not just because you’re tired of seeing the constant nose rubbing or “allergic salute.” Uncontrolled allergic rhinitis makes it harder to control asthma, if your child has that too. Other problems can stem from a chronically stuffy nose, such as ear and sinus infections (and possibly hearing loss), poor sleep and sleep apnea and chronic mouth breathing, which can cause overbites and create a “long face” due to poor sinus bone formation in the face, says Watson.