Allergic rhinitis is characterized by repeated sneezing, “runny nose”, itchy nose, watery eyes and eye irritation. When caused by pollen, it is called seasonal rhinitis or, more commonly, hay fever.

Find out more about this disease in this sheet.

What is allergic rhinitis?

Allergic rhinitis is characterized by repeated sneezing, “runny nose”, itchy nose, watery eyes and eye irritation. When caused by pollen, it is called seasonal rhinitis or, more commonly, hay fever.

These symptoms result from an abnormal sensitization and an overreaction of the immune system towards a substance foreign to the body called an allergen. Depending on the person, it may be plant pollen, mold, substances on animal hair or skin, or other particles. When this substance comes into contact with the eyes or respiratory tract of the allergic person, the immune system sets in motion an inflammatory reaction. Histamine and other inflammatory substances are then “unnecessarily” released. This reaction leads to the dilation of blood vessels and increased secretions linked to the appearance of symptoms of allergic rhinitis.

Allergic rhinitis usually appears between the ages of 5 and 20. According to the Canadian Allergy, Asthma and Immunology Foundation, 20% to 25% of Canadians suffer from allergic rhinitis. The symptoms tend to be more pronounced than before, according to the observation of several doctors. This phenomenon could be explained, among other things, by the increase in greenhouse gas emissions. These would in particular have the effect of increasing the production of pollen from plants and trees2.

Hay fever or persistent rhinitis?

Seasonal rhinitis: hay fever

Often called hay fever or “hay fever”, it appears periodically, most often in the spring and summer, when the allergenic plant blooms.

In early spring, tree pollen is frequently the cause, while in July, it is more grasses (meadow grasses, hay and lawns). People allergic to ragweed (Ambrosia artemisiifolia) suffer from it in late summer when the plant flowers. It should be noted that moulds, which are more important during snowmelt and lawn maintenance, can also trigger allergic rhinitis.

Symptoms of seasonal rhinitis are usually aggravated by country trips as well as exposure to the outdoors. People with allergies suffer less when it rains (the rain knocks pollen down to the ground) and when they stay indoors, with doors and windows closed.

What about “hay fever”? The expression originated at the beginning of the 19th century. At the time, doctors observed the symptoms especially in peasants, after the haying season. It was called fever because those who had it became restless. Anciently, restlessness was considered one of the characteristics of fever. Note: patients with allergic rhinitis do not have a fever.

Persistent rhinitis

The majority of people with persistent rhinitis have a condition called vasomotor rhinitis that is non-allergic. It usually appears after the age of 20, and often occurs in stressful situations. It is triggered by changes in temperature or humidity, in the presence of smoke, dust, strong chemical odors or in response to medication or hormonal changes.

Persistent rhinitis can also be caused by allergenic substances permanently present in the person’s environment, at home or at work. The affected person seems to have a constant cold. Dust, animals and certain molds are all possible triggers. The crisis often starts when you wake up and can repeat itself several times a day.

Dust mites are a very common cause of persistent allergic rhinitis. These are microscopic mites that feed on the scales of human skin. They like warm and humid environments. They are found in mattresses, pillows, sofas, carpets and dust. People who react to dust mites are actually allergic to their droppings.

Symptoms of allergic rhinitis

Symptoms persist as long as the person is exposed to allergens. Although hay fever symptoms reappear each year as the plant flowers, they tend to diminish with age. On the other hand, some people develop pollen allergies only in adulthood.

• Itchy, runny nose and very liquid secretions;
• itchy, watery and red eyes;
• serial sneezing;
• nasal congestion;
• tension in the sinus region;
• sore throat, hoarse voice or cough;
• itching in the throat or palate;
• impaired taste, smell and hearing (especially in children);
• fatigue, irritability and insomnia, when symptoms last for several days.

The causes of rhinitis

We do not know the exact causes of allergic rhinitis, but the genetic background would be a fairly important factor. Of a person who, by his genes, is more sensitive to allergies, we say that he has an “atopic terrain”. In other words, it overreacts to contact with normally commonplace and harmless allergens. This can lead to different manifestations: allergic rhinitis, asthma, hives, eczema, food allergies, conjunctivitis, etc. They can appear in isolation, simultaneously or successively, depending on the person.

Pollens are involved in seasonal allergic rhinitis. In Canada, ragweed remains the most important source of pollen. This is why public health authorities are conducting public awareness campaigns to eradicate this plant31. Quebecers are also advised to pull ragweed before it blooms in August.

Sources of pollen
Spring (mid-March to end of June)	Trees and shrubs
Summer (late May to mid-October)	Grasses (turf, hay, rye, wheat, corn)
Late summer (late July to October)	Ragweed

Consult the Allergies fact sheet to learn more about the factors responsible for the increase in cases of allergies in recent decades.

Allergic rhinitis: people at risk

• Heredity seems to play an important role in the onset of allergies, including allergic rhinitis. When both parents have an allergy (it doesn’t matter which one), the child’s risk of suffering from allergic rhinitis is all the higher;
• men are more at risk than women, for unknown reasons;
• the eldest of the family.

Allergic rhinitis: risk factors

• Repeated exposure to airborne allergens;
• Exposure to cigarette smoke, particularly during the first year of life ²⁸;
• Exposure to air pollution and other respiratory irritants (smoke from fireplaces, airborne pollutants) ^29,43-44;
• The abuse of topical (aerosol) decongestants can worsen the condition of the mucous membranes of the nose and, consequently, cause medicamentous (non-allergic) rhinitis.

Allergic rhinitis: possible complications

Even if symptoms are mild, untreated allergic rhinitis can worsen and lead to chronic sinusitis. Persistent rhinitis is often linked to asthma, regardless of the intensity of the symptoms. Finally, in children, allergic rhinitis increases the risk of otitis media.

When to consult for allergic rhinitis?

It is better to consult a doctor if:

• symptoms are persistent and affect quality of life;
• symptoms are not relieved by over-the-counter medications;
• the side effects of the drugs are poorly tolerated.

Allergic rhinitis: how to diagnose it?

It is sometimes possible to discover the allergen that is causing the rhinitis. The doctor takes a history of the symptoms: when they appear and how. The allergens present in the person’s environment (home, office, school) are then listed. By trial and error, we can find out which elements are actually allergenic. When the allergen is difficult to find or when the medication does not work, a skin or blood test is carried out.

Skin test: the skin is exposed to very small doses of purified allergenic substances. These substances can be pollen from various plants, mold, animal dander, dust mites, bee venom, latex, penicillin, etc. We then observe the signs of allergic reactions (redness or small bump similar to an insect bite) after about twenty minutes.

Blood test (or RAST for radioallergosorbent test): a blood sample is subjected to different allergens. If the patient is allergic, for example to birch pollen, the antibodies (IgE) specific to birch pollen will bind to this allergen. This test also provides information on the concentration of antibodies present in the blood in reaction to the allergen. Although more expensive, this technique has the advantage of being risk-free since it does not expose the person directly to allergens.