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Allergy

06 February 2020

Pollen allergies: These are the common trees, grasses and plants to avoid in SA

The increase in pollen may be posing a threat to your immune system, but there are ways to save yourself from the misery. Here’s what to look out for, and how you can manage symptoms.

Pollen, a fine powder that is produced by trees, grasses, weeds and flowers to fertilise other plants of the same species, is one of the most common triggers of hay fever (also known as allergic rhinitis).

Just a pinch of pollen contains thousands of pollen grains, and these small and light pollen grains travel through the air, propelled by wind. For this reason, they are known as airborne pollens.

Some people have an adverse immune response when they breathe in pollen – which is essentially harmless. This is because some people’s immune systems mistake pollen as a threat. When this happens, the immune system produces chemicals (histamines) to fight the perceived threat, the release of which brings about an allergic reaction. This reaction may cause several irritating symptoms, such as a runny nose, itchy eyes, nasal congestion, tightness of the chest, and sneezing.

Pollen allergy can leave you with allergic rhinitis, conjunctivitis or asthma. In somebody with asthma, when pollen is inhaled, it can trigger an asthma flare. Similarly, if someone is highly allergic to grass pollen and rolls around in grass, they can develop hives on their skin. 

Not all plant pollens are allergenic

While pollen is considered as the main component of aeroallergens that lead to rhinitis and asthma, not all pollen is allergenic, notes The Real Pollen Count. In fact, it is mainly windborne pollens – as opposed to insect pollinated plants – that are allergenic, and they usually stem from small plants like grasses that release millions of windborne pollen grains during spring.

Fynbos plants, for example, are pollinated by insects, birds, mice and bats, and their seeds are not windborne, which means that it cannot easily be inhaled.

According to the Real Pollen Count, the common culprits that produce highly allergenic pollen in South Africa are:

Trees

  • Cypress trees: release their allergenic pollen from June onwards.
  • Oak trees: allergenic pollen is released in spring.
  • Plane trees: flower from the end of August, and have a short pollen-release season of six weeks in spring.
  • Olive trees: common in public spaces in South Africa, and release allergenic pollen from October to March.
  • Elm trees: flower from October to March, releasing allergenic pollen during that time.
  • Rhus tree: a widely planted in South Africa that is mostly pollinated by insects, but pollen has been detected in air samples. It releases allergenic pollen from October to March.

Grasses

  • Ryegrass: flowers from late September.
  • Winter grass: produces tiny grass flowers in June in winter rainfall areas.
  • Wild oat grass: appears in midwinter in some areas, but takes a few weeks to grow to its maximum height of 0.3–1.2cm before it releases pollen.
  • Bunny tail grass: appears in September–October.
  • Thatching grass: this grass is very tall and is mostly found in the grassland areas of Gauteng and the Eastern Cape. It releases pollen from September to June.
  • Bermuda grass: releases most of its pollen in late summer, but it may be found throughout the year.
  • Buffalo grass: a coastal grass that may be seen in the Cape, especially along the east coast and on the Otter Trail between Knysna and Nature’s Valley. Up to 80% of South Africans react to Buffalo grass pollens.
  • Kikuyu: is favoured as a lawn grass, and you should take care that the nursery is selling the female grass seedlings that do not produce pollen, suggests The Real Pollen Count. 

Weeds

  • English plantain: widespread throughout South Africa and is seen during most months of the year, although its peak flowering season is in December.
  • Dandelion: its peak flowering time is late summer-autumn.
  • Reeds: different species flower at different times of the year, and their pollen is therefore present in the air all year long.
  • Daisies/Cosmos: November and March are the peak months for these weeds.
  • Heath: these are fynbos plants, and although fynbos is mostly insect-pollinated, pollen from species of this genus is constantly found in air samples from July until March.

Grasses and trees are the most common causes of pollen allergies. In the US, ragweed is a main cause of weed allergies, but it has only recently been spotted in South Africa.

“I don’t think there’s an area [in South Africa] that is totally low allergy,” Professor Jonny Peter, head of the UCT Lung Institute's Allergy and Immunology Unit told Business Insider. “It is more of a case of what your particular allergens are.”

Managing symptoms

Although a pollen allergy is unlikely to go away once it has developed, symptoms can be treated with medications and allergy shots. However, certain lifestyle choices can also help to relieve symptoms. On high pollen count days, you should therefore:

  • Stay indoors when it’s windy.
  • Don’t leave washing on the line for too long.
  • Keep windows closed on high pollen count days.
  • Take a shower and change your clothing when you’ve been outdoors.

You can check the weekly pollen counts here.

Before you stock up on antihistamines, it is best to consult your doctor about specific treatment options. An allergy specialist can also perform skin prick or blood tests and confirm if you have any particular allergy triggers.

As the pollen problem worsens, precise and expanded monitoring becomes even more essential. And here's how you can help.

Amid the highest recorded pollen counts in history, Health24 will be bringing you exclusive weekly pollen count updates courtesy of the UCT Lung Institute's Allergy and Immunology Unit.

Image: iStock

 

Ask the Expert

Allergy expert

Dr Morris is the Principal Allergist at the Cape Town and Johannesburg Allergy Clinics with postgraduate diplomas in Allergology, Dermatology, Paediatrics and Family Medicine dealing with both adult and childhood allergies.

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