Mould Allergy

Moulds are naturally occurring clusters of microscopic fungi which reproduce by releasing airborne spores. Certain individuals will develop asthma and nasal symptoms if they breathe in these spores and thus have a mould allergy. Moulds are typically found in higher concentrations in coastal areas and especially in the subtropical parts of the country. The mould spores tend to be released all year round and are found in both damp indoor and outdoor environments. If airborne mould spore levels exceed 3 000 spores per cubic meter of air, allergic symptoms are likely to occur in susceptible individuals. Moulds thrive in warm humid places and spore counts tend to peak in Spring and Autumn. Up to 20% of asthmatic patients may be allergic to moulds and are often allergic to more than one type of mould. Moulds play an important role in decomposing vegetable matter and can be found in all parts of the country, e.g. the natural grasslands during the Winter months or where crops such as grapes, maize or wheat are grown in abundance.

Common Allergy Provoking Moulds found in South Africa:

*ALTERNARIA: Found on rotting vegetation and in damp indoor areas, appears to be an important allergenic mould in most parts of the country.

*CLADOSPRORIUM: Found in both indoor and outdoor environments, especially in wooded areas. This is the common allergy provoking mould in all parts of South Africa.

*EPICOCCUM: Found on decaying vegetation and especially on seaweed; is highly allergenic.

*ASPERGILLUS: Grows on cereal grains, is found in barns and indoors in damp homes; especially in bathrooms.

*PENICLLIUM: Common on spoiled food and in wine cellars but is less allergy provoking than the other moulds.

Mould control measures in the home

*General control measures:

Ensure home is adequately ventilated or aired, as closed houses prevent the escape of moisture and encourage mould growth. Limit the number of indoor house plants. Dehumidifiers may be used if available. Do not store firewood indoors. Wipe down mould infested surfaces, walls and ceilings with bleach or apply mould resistant paint.

*The Kitchen:

Use of extractor fans (if available) will remove steam produced during cooking or boiling of kettle. Make sure water pans below self-defrosting refrigerators are frequently emptied. Tumble-driers can also increase indoor humidity and promote mould growth. Rubbish bins should be emptied and cleaned frequently.

*The Bathroom:

Open all windows after showering or bathing. Wash down shower curtains, tiles, shower cubicle, bath, and ceiling with household bleaches such as Jik or Milton which kill moulds. Do not carpet the bathroom. Air all cupboards frequently. If cupboards are damp use louvre doors instead of solid doors. Hang damp towels in sunshine to dry.

*The Bedroom:

Replace fitted carpets with linoleum or floor tiles. Encase the mattress and pillow in impermeable synthetic covers, remove indoor plants and never store food in the bedrooms. Dry away any condensation on windows. Wipe down damp window frames. Air cupboards and never store damp shoes, clothing, luggage, or leather goods in cupboards. Curtains, wood panelling and wallpaper may support the growth of moulds. Humidifiers and steamers used to treat croup will promote mould growth in the bedroom. A low wattage (40w) light bulb or chemical moisture remover will limit mould growth if replaced in cupboards.


Allergic people should avoid cutting grass and especially old grass cuttings. They should not rake leaves and must wear a mask over their nose and mouth if they must carry out these activities. Mould spores are most prevalent on dry and windy days. Avoid exposure to soil, compost piles, sandboxes, hay, vines and barns. Feed stores on farms are full of moulds. Correct water drainage problems near the house as pooled water increases mould formation. Avoid camping or walking in forests or densely vegetated areas especially during Autumn and Winter months when there are a lot of dead leaves on the grounds.

Occupational Exposure

Farmers, gardeners, bakers, brewers, florists, carpenters, mill workers, wine makers and wallpaper hangers are most at risk for developing mould allergy. Faulty air-conditioners can harbour and distribute moulds. Greenhouse and wine cellars tend to encourage mould growth.

Diagnosis and Treatment

The patient will often have a history of mould related asthma and nasal symptoms. Mould allergy can then be confirmed by blood tests and skin prick testing with extracts of the various moulds.

Initial treatment would entail mould removal or avoidance followed by medical treatment of the asthma and nasal symptoms that may have been triggered by the mould.