Medical Chronicle November/December 2013 | Page 28

ALLERGY

Climate change, pollution and allergies
The following article is based on a presentation by Dr Maurice Hockman of the Netcare Linksfield Hospital.
Pollen allergens in SA
Through pollen monitoring, specific
pollen counts are measured, i.e. the
number of grains or fungal spores
per cubic metre. This a measure of
the likelihood of symptoms of hay
fever, conjunctivitis, rhinitis or asthma
occurring in sensitised patients.

Long-term aero-biological data
exist for the Western Cape only, in
suburbs at the coast, inland and
coastal table mountain. Shortterm studies have been carried
out in Pretoria, Johannesburg,
Vanderbijlpark, Durban, Richards Bay
and Secunda.

Grass was found to be the major
pollen allergen in most cities.
Tropical Durban had the highest
fungal spore load.
Skin-prick testing in Bloemfontein
identified grass and maize as
important allergens.
Recent studies suggest a correlation

between pollution and allergen levels
with increased patient symptoms and
disease incidence, but more healthcare
impact studies are still needed.
Planning for adequate humidity
control and optimum air filtration and
ventilation could benefit people who
suffer from outer allergies as well as
allergies to indoor allergens.
Improved anticipatory public health
messaging such as pollen alerts could
help prevent exposure that increases
risk of not only disease symptoms but
also disease development.
Ultimately, the health impacts
of climate change and air pollution will depend on public health
adaptation strategies.

Projected impact of climate
change on allergic disease
Global warming induced by human activity has an impact on the
biosphere and the environment.
Greenhouse gas emissions due to
human activity have been growing
for many years, with an increase of
70% between 1970 and 2004. The
fourth report of the Intergovernmental Panel on Climate Change,
February 2007, demonstrated that
global temperature has risen markedly over the last 30 years.

Conclusion
We live in a dynamic environment
with increasing average temperature
and increasing anthropogenic
greenhouse gases that may lead
to increased production of pollen
producing plant species.
Increased pollutant levels such as
carbon dioxide, ozone and nitrous oxide
enhance the allergic response.
These changes in the climate are
expected to alter the presentation
and epidemiology of allergic rhinitis
in other allergic respiratory diseases.
SA urgently needs pollen sampling
studies in areas where pollen profiles
have not been researched, in order
to identify the relevant allergens of
individual cities.
A national database should
be set up, where skin prick and
ImmunoCap RAST will be audited
in state and private allergy clinics. A
start has been made in this direction
with the Lancet Lab’s assessment
presented at SAARWG in 2012
by Prof Vardas and this should be
formalised.
References available on request.

28 MEDICAL CHRONICLE NOVEMBER/DECEMBER 2013