1. Seasonal allergic rhinoconjunctivitis is most prevalent in Ontario, where silver birch is a major culprit, and least common in the Atlantic. The Prairies have a special problem with snow mould spores, which appear almost as soon as the snow melts, causing an early spike in symptoms.

2. Don’t wait for symptoms to appear, but start patients on topical medication (whether steroid or antihistamine) about 2 weeks before the offending pollen is expected, or 2 weeks before the date on which symptoms appeared last year.

3. Antihistamines are the mainstay of treatment in most cases — topical first line, oral second. Topical steroids are reserved for more severe cases, especially those with nasal obstruction, which antihistamines rarely resolve. Intramuscular steroids are unjustifiable. Oral steroids can be given briefly at key times, like exams or weddings.

4. Decongestants can help, but their main purpose should be to open nasal passages for deeper penetration of topical steroids or antihistamines. Chronic use will cause rebound congestion after about a week.

5. Avoid first-generation antihistamines (chlorphenamine, terfenadine, hydroxyzine) for their unacceptable sedative and cardio effects. Second-generation antihistamines (cetirizine, loratadine, fexofenadine) offer a large improvement over Gen 1 drugs for a small price increase. Third-generation antihistamines (levocetirizine, desloratadine) offer a small further improvement for a largish price increase. Reserve these for those who still feel sedated on Gen 2 drugs.

6. Pollen rises with hot air in the morning, and falls with cold air at night. It’s most concentrated in our air at late morning and early evening, so these are good times to be indoors. Evening pollen counts peak later in the city, as the air stays warm longer.

7. Pollen avoidance works. Changing clothes and showering after being outdoors makes a real difference. Advise patients to tumble-dry their clothes rather than hang them outside. Petrolatum jelly in the lower nostrils can block some pollen, and nasal rinsing with saline helps clear some more. Sunglasses reduce conjunctivitis.

8. Closing windows and using air conditioning is helpful both at home and in the car. Most modern cars with AC have filters that stop pollen.

9. Hay fever patients are great experimenters in complementary medicine. There’s a persistent, unverified rumour that eating local honey before pollen season helps grass allergies. The only herbal remedy to show efficacy in trials is butterbur, with an effect similar to antihistamines. But its safety is unproven and the plant has known liver toxicity and carcinogenicity.

10. If all else fails, the final recourse is desensitization immunotherapy. Only one such treatment is approved by Health Canada, Pollinex-R, a 4-shot course for ragweed. Densensitization has a long and sometimes murky history, but is making a comeback and many specialists believe it holds great promise. Expect to see more on this front, including new oral treatments.