Spore Allergen

The Spores FAQ

Frequently asked questions regarding spores and spore allergenicity. Please choose a question from the list below, or scroll down to read our answers.

What is mould (fungus)?
There are thousands of types of moulds and yeasts. Both can cause allergic reactions, however, only a very small number are known to be allergenic. There is still a lot to learn about this group. A well known example of a mould is Penicillium. The most common place to find this mould is on bread. There are many other types of moulds which grow in many places. Dead vegetation, plants, food, indoor and outdoor air, carpets, drywall and many other places support the growth of moulds and yeasts. Some fungi, such as the mushrooms, are even edible. (top)

What are spores?
Spores are the reproductive particles or seeds of fungi. There are many different types, sizes and shapes. The allergenic properties of many of the spores are unknown. These are the particles that are released in the air by the moulds and are inhaled. (top)

Where are moulds found?
Moulds are found nearly everywhere. Please see the spore allergen database which gives more information on this topic. (top)

How are spores collected and counted?
Spores are counted and collected using the same methodology as is used to collect pollen. Please refer to the Pollen FAQ. (top)

Why do moulds cause allergies?
Spores, which contain proteins, are released by the fungi and are inhaled by people. Many of the spores are ambient and do not cause allergic reactions. We know of some that are involved in allergic responses but there are thousands of spores found in air samples that are not understood. Spores are generally smaller than pollen grains and can get deeper into the lungs. This allows them to be more active in causing asthma than the larger pollen grains, which do not usually get deep into the lungs and are more involved in causing upper respiratory tract problems. This does not mean that pollen do not cause asthma since small fragments of pollen and plants are often found in the air and can travel deep into the lungs. Fungal spores are also a problem in food and buildings. Moulds cause food rot and when eaten can make a person can have an allergic reaction. Some produce toxins, which can be found in the food even if the mould is not visible, and can cause illness. (top)

Which moulds are allergenic?
Mould spores are important airborne allergens when abundant. They are easily carried by air currents and are allergenic in their chemical makeup or the proteins they carry. They are found almost everywhere, including indoors. Some are known to cause asthma and allergic reactions, for example, Coprinus, which is a mushroom, produces a high number of spores which are released in the air and are considered important in causing disease. There are many other spores where nothing is known about their chemical makeup or their involvement in causing disease. (top)

Are mould counts important?
Yes. A lot can be learnt about the association between spore counts and allergic responses. This can be related to what is actually in the air and the effectiveness of a treatment program. (top)

How can I avoid spores when I have allergies?
Fungal spores are more difficult to avoid than pollen. They are found in food, indoor and outdoor air, actually everywhere. This makes it hard to avoid them but it is possible to reduce the amount of exposure. Staying indoors when the spore levels are high, having a filtration system and good ventilation in the home and workplace, and take measures to reduce humidity thus limiting growth of fungi. Keeping dust in the home to a minimum, eliminating carpets, and keeping the refrigerator free from mouldy food are some of the ways one can reduce mould exposure. (top)


The information presented here is designed to inform, not replace, the relationship that exists between a patient and a medical professional.

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