Moulds or fungi are very small living organisms, related to the
mushroom family, that grow in almost any environment on Earth
except from the Polar Regions.
The allergy to moulds is caused by mould spores. These are very
small particles (much like the seeds of the plants) which are
released in the air by the adult fungi in order to
multiply.
There is a very large variety of moulds existent on Earth; they can
be found both in the outdoor or indoor environment. The fungi
species growing outdoors differ from those growing indoors.
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Allergens > Airborne allergens
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| > Moulds |
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Moulds
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When are mould spores more likely to be present in the air?
Moulds growth occurs all year round but both their growth and the
spore release is very much affected by the weather conditions.
Their ideal growing and spore release conditions include high
humidity (>65% relative air humidity) and temperatures between
18 - 32° C. These are the weather conditions found in tropical
regions where moulds find the most adequate growing
habitat.
Due to these requirements, concentration of outdoor moulds is subject to seasonal variations according to changes in the temperature and humidity: the concentration of outdoor mould spores is lower during winter; it begins to rise in spring, paralleling the warming of the atmosphere and reaches the peak levels at the end of summer and throughout autumn, when both humidity and air temperature offer the best growing conditions. As a consequence of these growing particularities people allergic due to outdoor fungi manifest symptoms only during certain periods of time along the year.
Indoor moulds are less subject to seasonal variations due to relatively constant characteristics of the indoor environment. People allergic to indoor fungi are generally developing symptoms all year round.
Due to these requirements, concentration of outdoor moulds is subject to seasonal variations according to changes in the temperature and humidity: the concentration of outdoor mould spores is lower during winter; it begins to rise in spring, paralleling the warming of the atmosphere and reaches the peak levels at the end of summer and throughout autumn, when both humidity and air temperature offer the best growing conditions. As a consequence of these growing particularities people allergic due to outdoor fungi manifest symptoms only during certain periods of time along the year.
Indoor moulds are less subject to seasonal variations due to relatively constant characteristics of the indoor environment. People allergic to indoor fungi are generally developing symptoms all year round.
Tip: remember that the risk of mould exposure is higher during the
warm, moist and windy days. Try to avoid outdoor activities during
those days.
Where do fungi grow?
- Indoor fungi grow inside the buildings, in the areas with high humidity such as the bathrooms, basements, attics, laundry and storage rooms. The most common indoor airborne moulds are Penicillium and Aspergillus species.
- Outdoor fungi grow particularly in the areas with abundant plant growing and also on decaying vegetation which ensure the humidity (and also the food) they need for growing. Outdoor allergenic moulds include Alternaria and Cladosporium species.
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| Fig. 4 Indoor and outdoor moulds: moulds growing on rotten food (A), indoor wall with excessive humidity and moulds (B), bathroom tiles with mould stains (C), moulds growing on a flower pot (on the soil and decaying leaves)(D) moulds growing on outdoor fallen leaves(E) |
What kind of allergic diseases can be caused by moulds?
Mould spores are very small particles that are easily inhaled up to
the lungs. Most often they cause asthma but rhinitis and allergic
conjunctivitis can also be an expression of mould allergy.
How to reduce exposure to moulds?
Similar with pollens, it is very difficult to avoid exposure to
mould spores. Complete avoidance is usually impossible; following
measures can help you reduce the concentration of mould spores in
your house and also the contact with outdoor moulds.
DO…
| DON’T…
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