From Kathleen MacNaughton, R.N.,
Your Guide to Asthma.
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Mold and its spores are a powerful allergen in people who have allergic asthma with a sensitivity to mold. Mold can grow both inside and out, so it can be an indoor asthma trigger, as well as an outdoor asthma trigger.

What Mold Is

Molds are a type of fungi, too small to be seen with the naked eye. They are related to mushrooms, but do not have stems, roots, or leaves as mushrooms do.

Instead, they have lightweight spores that can float through the air somewhat like pollen spores do. The most common types of molds that are asthma triggers include:

• alternaria
• cladosporium
• aspergillus

Molds As Outdoor Asthma Triggers

Although molds are allergens as are pollens, they don't have a specific growing season. Their growth is related more to environmental factors such as heat, wind and humidity rather than a time of year.

Depending on where you live, molds can be present in the outdoor environment throughout the year. However, in areas with well-defined seasons and cold temperatures in the winter, molds tend to appear in greater numbers after a spring thaw. They'll reach peak levels during July in warmer areas and October in cooler areas.

In temperate climates such as the southern U.S. and western U.S. coast, outdoor molds may be active year-round.

Outdoor molds are found in piles of dead leaves, soil, vegetation and rotting wood. So, it's best to avoid those areas if you are sensitive to mold or notice your asthma symptoms worsening when you are outdoors.

Molds As Indoor Triggers

Indoor molds can be found year-round, which means, if present, they can trigger your asthma symptoms at almost any time.

Molds love damp, dark environments; so they can most commonly be found in basements, attics, bathrooms, refrigerators and other places where food is stored, under kitchen sinks, garbage containers, and in carpeting and upholstery.

If you think you may be allergic to mold, keeping a symptom / trigger diary can help you gather more clues. Note when your asthma symptoms occur, where you were beforehand and what you were doing. If patterns emerge, talk with your doctor about whether allergy testing would be helpful.

There are some steps you can take to avoid molds too. And if you notice improvement when you do so, it may be further evidence of your sensitivity to mold as an asthma trigger.

_Source:

AAAAI, "Tips to remember: outdoor allergens." American Academy of Allergy Asthma & Immunology. 01 January 2006. AAAAI. 18 Oct 2007 http://www.aaaai.org/patients/publicedmat/tips/outdoorallergens.stm.