An allergy is an exaggerated immune reaction to a normally harmless substance known as an allergen. When a susceptible person is first exposed to an allergen, the immune system does not necessarily react, but stores this foreign substance in its memory. Later re-exposure may result in antibodies releasing substances, such as histamine, triggering a range of reactions.
Allergies vary in intensity and can take many forms including atopic dermatitis (eczema), asthma, and allergic rhinitis.
Allergy sufferers may experience one or several of the following symptoms:
There are two types of allergic rhinitis:
- Seasonal (acute): occurs at specific times of the year only (e.g., ragweed, tree and grass pollen);
- Perennial (chronic): occurs year-round, usually a reaction to indoor allergens (e.g., dust mites, pet dander, mould).
Causes and triggers
The tendency to develop allergies appears to be hereditary. If one or both parents suffer from allergies, their children are more likely to develop allergies.
Prevention and treatment
The best prevention is to avoid contact with allergens. Since this is not always possible, try to limit exposure. To reduce allergy symptoms:
Caused by dust and dust mites:
During pollen season (when pollen is carried by the wind):
There is a vast array of treatments available, and many of them are available without a prescription. Generally speaking, starting treatment before exposure to the allergen is more effective than starting when symptoms are already present. Speak to your pharmacist to see which product is best for you.
The use of a saline solution to irrigate the nasal passages may help improve symptoms of allergic rhinitis.
Another option is allergy desensitization. This involves the administration of small amounts of allergy-triggering substances to build tolerance, reducing the intensity of symptoms upon re-exposure.
When should I see a healthcare professional?
Consult your healthcare professional if:
- Your symptoms persist or prevent you from doing your daily activities as you usually would;
- Over-the-counter drugs do not relieve your symptoms;
- Drugs cause side effects that your body does not tolerate.
To participate in your diagnosis, provide your doctor with basic information such as symptoms, time of day or season, and substances believed to be responsible. Painless skin tests may also be ordered.
For more information:
Canadian Society of Allergy and Clinical Immunology