There does seem to be an increase in allergies, with about 30 per cent of adults and 40 per cent of children affected in Canada. This trend is thought to be due to several factors, including the fact that today we are able to diagnose allergies that previously may have been dismissed as a sensitive stomach or dry skin.
As well, allergens (i.e. the substances that cause allergic reactions) are also more numerous today and exposure to them is more likely, for example with the number and types of drugs having increased in recent decades, and with nut products being more widely used in processed foods such as granola bars. Environmental exposure and exposure by contact is also more common because more different types of chemicals are around us.
An allergy is your body’s attempt to rid itself of a foreign substance that you have breathed in, eaten, or even touched. The immune system produces antibodies to the foreign substance or allergen, and the result is a release of substances such as histamine and leukotrienes which cause the swelling, itching, and redness that are the symptoms of the allergy.
It can take several exposures to the allergen to produce the reaction because it can take your body several exposures to produce the numbers of antibodies needed to elicit the allergic reaction. (It is a myth that you suddenly become allergic to a substance. Instead, it just takes time for your immune system to manufacture the antibodies.)
If members of your family have allergies, then you also have a good chance of having allergies. Age can be a factor too, with more children than adults being affected, although allergies in the elderly are more difficult to diagnose because of the greater number of drugs and medical conditions that may be involved.
Sometimes where you work, play, or even live can play a role. For example, working outdoors on a farm may mean you may be more susceptible to pollen and plant material or even livestock. Other environmental factors such as tobacco smoke, cold air, or even stress can also be implicated.
Keeping a diary of your activities including your diet may help you pinpoint what makes an allergy worse or improves it.
Environmental allergies can be linked to pollen from trees, grasses, and weeds, mould, cat or dog dander, dust mites, and inhaled chemicals… that is, just about anything to which you may be exposed. Allergic rhinitis or hay fever affects anywhere from 10 to 30 per cent of the population, although it may be under-reported because many sufferers self-treat with non-prescription products.
Skin allergies are largely caused by touching something to which you are allergic, for example poison ivy, dish soap, or metal jewelry. These allergies are termed contact dermatitis, and a variety of symptoms can be produced ranging from rashes to eczema and hives. Often skin allergies resolve on their own or are treated with non-prescription products. Thus they tend to be under-reported and those that are reported tend to be more serious. (Latex skin allergies do seem to be reported more consistently by health-care professionals who need to wear latex gloves, with one to six per cent of them being affected.)
Food allergies affect six to eight per cent of children and four per cent of adults, with peanuts accounting for about one per cent of cases. Peanuts are the most common cause of food allergies, followed by milk, then shellfish. However, some incidents of stomach irritation may be misidentified as an allergy.
Drug allergies affect about 10 per cent of the population. Penicillin is most often implicated, but other antibiotics, supplements derived from plants, and non-steroidal anti-inflammatory drugs like ibuprofen can also cause an allergic response. Insect stings like bee and wasp stings are painful, but also produce a severe allergic reaction in about five per cent of people.
Antihistamines are ideal for allergies, but need to be taken soon enough after symptoms begin in order to be most effective in blocking the effects of histamine. That means you should take your antihistamine for your cat allergy before you visit your grandmother and her cats.
Severe allergic reactions (i.e. anaphylaxis) can mean swelling and edema of the throat, inability to breathe, low blood pressure, wheezing, and severely itchy skin. Epinephrine is a hormone that is able to constrict blood vessels and open airways. It is available as an automatic injection EpiPen, which can be administered for anaphylaxis. If you have a severe reaction to anything, you should always carry an EpiPen with you. Don’t leave home without it!