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Amongst the fungi, Aspergillus fumigatus is the most prevalent cause of severe pulmonary allergic disease, including allergic bronchopulmonary aspergillosis (ABPA), known to be associated with chronic lung injury and deterioration in pulmonary function in people with chronic asthma and cystic fibrosis (CF).



Found worldwide, Aspergillus fumigatus can colonize in the bronchial tracts of asthmatics, causing severe asthma and low lung functions and sometimes leading to severe conditions.

Within the larger Aspergillus genus, Aspergillus fumigatus is typically blue-green to gray in color with a woolly or cotton-like texture. Although Aspergillus is considered a seasonal outdoor mold that's often found on decaying vegetation, it can also colonize indoor environments such as air-conditioning systems, and it's one of the three most common indoor airborne fungi (along with Penicillium and Cladosporium).

Aspergillus requires minimal moisture, and some species tolerate very dry conditions. As such, Aspergillus can grow rapidly in areas that can't support other molds. It produces small, dry, and easily aerosolized spores, which make them a significant indoor air contaminant. If you're allergic to Aspergillus fumigatus, you may experience symptoms after inhaling its spores.

Where is Aspergillus found?

Aspergillus fumigatus can grow both indoors and outside. Outdoors it prefers environments such as soil, decomposing leaves, bird droppings, compost, wood chips, hay, stored grains and sweet potatoes, and hay and other crops.

However, mold reproduces via spores, which can be transported by air, water, and insects.

So even if a fungus originates outdoors, it often can enter a dwelling through a variety of means, including doorways, windows, vents, and heating and air conditioning systems.

Aspergillus can grow on indoor surfaces such as ventilation ducts, floors, walls, potted plants, and household dust, and it's often found on foods rich in starch, such as rice, cereal, and bread. However, it has also been known to invade cereal grains and grow on processed and cured meats.

It grows optimally in temps 37 to 43 C (roughly 99 to 109 F), but it can tolerate temps of 12 to 57 C (approximately 54 to 135 F).

While Aspergillus fumigatus has almost worldwide distribution, in-home prevalence varies widely. For example, in the United States it was found in the air of 2.9 percent of homes in Southern California, but it was measured in 4.5 percent of homes in the Netherlands.

Common Symptoms

Mold allergy symptoms can range from mild to severe and vary person to person. Reactions can happen almost immediately after exposure, or they can be delayed. Symptoms are most common in mid-summer to early fall, but since molds grow both indoors and out, allergic reactions can occur all year.

Symptoms typically include one or more of the following:

→ Nasal congestion

→ Runny nose

→ Sneezing

→ Irritated, watery eyes

→ Coughing

→ Wheezing

→ Itchy eyes, nose, and throat

→ Dry, scaly skin

Mold sensitization is also a major risk factor for developing upper and lower respiratory diseases such as allergic rhinitis (aka hay fever) and allergic asthma.

Aspergillus fumigatus can also colonize in the bronchial tracts of asthmatics, causing severe asthma and low lung functions, sometimes leading to severe conditions called allergic bronchopulmonary aspergillosis (ABPA) and allergic bronchopulmonary mycoses (ABPM).

The condition involves both an allergic and inflammatory response to mold, and symptoms may include severe wheezing, coughing, shortness of breath, fever, weakness/malaise, and cough producing brown flecks or bloody mucus.

In fact, Aspergillus fumigatus is the most frequent cause of 80 percent of all Aspergillus-related conditions including asthma, allergic sinusitis, hypersensitivity pneumonitis, severe asthma with fungal sensitization (SAFS), and ABPA.

In terms of prevalence, ABPA has been reported to occur in up to 40 percent of individuals with chronic asthma and up to 10 percent of those with cystic fibrosis.

In addition, other reactions to Aspergillus can include hypersensitivity pneumonitis (also known as extrinsic allergic alveolitis), which can lead to a chronic disease with irreversible lung damage.

A small percentage of asthmatics with inhaled mold allergy can also develop allergic urticaria (aka hives) when they eat or drink anything containing yeast or mold.

In addition to causing allergic reactions, molds can lead to infections along with toxic reactions.

How do I manage my allergy?

If you are allergic to mold, your healthcare provider may recommend a plan that includes the following.

Exposure Reduction:

→ Limit your outdoor time during seasons when mold is most active.

→ Wear a mask when disturbing or moving plant materials, and avoid raking and burning dry leaves.

→ Avoid barns, silos, hay, straw, and peat moss.

→ Use a certified asthma and allergy friendly filter attachment on your heating and air conditioning unit, and change filters regularly.

→ Employ dehumidifiers to lower indoor humidity levels to less than 45 percent to create an environment where mold is less likely to thrive.

→ Improve air flow through rooms by opening doors between spaces, moving furniture away from the walls, and operating fans.

→ Use exhaust fans in bathrooms and kitchens to pull moisture out of the rooms.

→ Fix any plumbing leaks, check windows for condensation, and remove sources of dampness.

→ Repair roof leaks, clean gutters, and ensure rainwater drains away from your dwelling.

→ Clean thoroughly and regularly, including sinks and tubs, refrigerator door gaskets, and garbage cans.

→ Remove clothes from washing machines promptly and clean rubber seals regularly.

→ Eliminate sources of dampness in basements, such as pipe leaks and groundwater seepage.

→ Run ventilation fans during and after showers and baths.

→ Remove any carpet from bathrooms and basements.

Symptom Relief:

Your healthcare provider may direct you to take one of the following medications to improve your allergy symptoms:

→ Antihistamines are commonly used to reduce symptoms such as sneezing, itching, and runny nose.

→ Nasal corticosteroids are used to reduce swelling in the nose and block allergic reactions.

→ Oral and nasal spray decongestants can be employed to relieve stuffiness.

→ Anti-inflammatories such as montelukast, which can be effective in treating mold allergy.

→ Daily nasal lavage using a squeeze bottle filled with salt water can help clean out irritants and alleviate nasal symptoms.


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