What causes hay fever?

Hay fever — often called allergic rhinitis — is one of the most common allergic conditions in South Africa. It affects children and adults alike, especially during spring and summer when pollen counts rise. But hay fever isn’t limited to the outdoors; indoor allergens can play a role too.

So, what actually causes hay fever, and why do so many South Africans experience it?

1. The immune system’s overreaction

Hay fever happens when the immune system overreacts to harmless particles in the air. Substances like pollen or dust are mistaken as threats. The body releases histamine, leading to sneezing, itchy eyes, a runny nose, and even fatigue.

2. Common triggers in South Africa

• Pollen
  • Grass pollen is a major trigger in SA, especially in the Free State and Gauteng during late spring and summer.
  • Tree pollen, such as acacia, plane, oak, and eucalyptus, can affect sufferers earlier in the season.
  • Weed pollen, including from plants like khakibos (Parthenium weed), also contributes to flare-ups.
• Indoor allergens
  • Dust mites thrive in warmer, humid coastal areas like KwaZulu-Natal and the Eastern Cape.
  • Pet dander from cats and dogs is a common year-round trigger.
  • Mould spores, especially in damp homes or poorly ventilated spaces, can worsen symptoms.
• Environmental irritants
  • Air pollution in big cities like Johannesburg, Pretoria, and Cape Town, as well as cigarette smoke, can aggravate hay fever symptoms.

3. Who is at risk?

• People with a family history of allergies, eczema, or asthma.
• Children exposed to tobacco smoke early in life.
• People living in urban areas, where air pollution interacts with pollen.
• Individuals with asthma or eczema — these conditions often overlap with hay fever in what’s called the “allergic triad.”

4. Why hay fever feels worse in SA

• Long pollen season: Unlike parts of Europe where pollen is more seasonal, South Africa’s mild climate means pollen can circulate for much of the year.
• Climate change: Rising temperatures and CO₂ levels are linked to higher pollen counts and longer flowering periods.
• Urbanisation: Dust, smog, and car emissions intensify allergic reactions.

5. Lifestyle examples South Africans know too well

• In Bloemfontein, families often notice grass pollen flaring up just as exams roll around, making it hard for learners to concentrate.
• Durban residents may struggle more with dust mites and mould due to the humid subtropical climate.
• In Johannesburg, high levels of air pollution can make pollen-related symptoms worse, especially during windy spring days.

6. The science behind the symptoms

• Immediate reaction: Within minutes of exposure, histamine causes sneezing, itching, and a runny nose.
• Late-phase reaction: Hours later, inflammation keeps the nose blocked and eyes watery, often leading to fatigue.

7. When to see a doctor

If hay fever affects your daily life — disturbing sleep, triggering asthma, or reducing productivity — it’s best to consult a GP or allergist. In South Africa, skin-prick tests or blood tests can identify specific allergens, and treatments range from antihistamines to immunotherapy (allergy desensitisation).

Final thoughts

Hay fever is more than an inconvenience — it’s the result of your immune system misfiring against otherwise harmless substances. In South Africa, grass and tree pollens, combined with indoor triggers like dust mites and mould, are common culprits. By knowing your triggers and managing exposure, you can reduce symptoms and enjoy life more fully — even during high-pollen season.

References

• MyDynamics: Hay fever (allergic rhinitis)
• Mayo Clinic: Hay fever causes and risk factors
• News-Medical: What causes hay fever?
• Medical News Today: Hay fever overview
• Cleveland Clinic: Allergic rhinitis overview

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