Mold Allergy

Mold allergy is usually considered as perennial allergic rhinitis because symptoms can be experienced all year long. Outdoors, mold may go dormant in climates with cold winters but indoors, it grows all year long. It is in winter that homes are closed up tight and fungi have the potential to cause health problems.

All of us are exposed to mold spores. There is no way to avoid them. For most people, they are not a bother and people don’t even know that they are surrounded by the microscopic particles. But for others, their immune system has become sensitized to the spores because their immune system is responding as if they were a foreign invader.

The Allergen

The cause of mold allergy is the spores that the mold colony produces. The function of mold spores is to reproduce for the colony just like pollen reproduces for the ragweed plant.

Reproduction
To insure its survival, mold colonies produce millions to billions of mold spores. When the colony is disturbed directly or by the wind, the spores are released. There is more mold spores in the air than anything else. Spores are on just about everything (even on a lot of the food that we bring home from the grocery store). If the spore lands on a surface with moisture and nutrients, it will start to grow into a new colony. If the conditions are not right for growth, the spore can remain dormant until it gets the moisture (directly or by condensation or humidity) that it needs. Once the mold spore begins to grow, it will produce a colony that in turn will produce millions more of mold spores that will be released into the air.

Particle Size
Mold spores are extremely small and can only be seen with a microscope. As a result, they are light weight which makes them easily dispersed by air movement and can stay airborne for a long period of time. This ability to stay airborne allows them to travel long distances. Furthermore, they can find other means of transportation by hitching a ride on the fur of our pets, our clothing, our shoes, and even the things that we carry into our homes.

Mold spores can measure between 3-12 microns in size. The particle size of the mold spores is very significant. The human eye can see down to about 100 microns which is roughly the width of a human hair. Particle size under 40 microns can have an effect on the eyes along with the nose. Allergen size under 15 microns can get past the nose and reach down into the bronchi tubes. Mold spores fit into this category. Consequently, people with asthma can be affected even if they do not have a mold allergy.

The Allergic Reaction

The Immune System
As the allergen is inhaled, the immune system sees the mold spore as something that it needs to protect itself from. The allergic reaction begins by the immune system producing an antibody called immunoglobulin E (IgE). This IgE antibody is made specifically for mold spores. If the person is allergic to another allergen, another type of IgE antibody would be made specifically for that allergen. This is one of the characteristic differences between some one who has a mold allergy and some one who does not. The person with allergies has a lot more IgE antibodies in their blood stream.

Sensitized
As the body produces a large supply of mold spore specific IgE antibodies, they then attach themselves to mast cells. At this point, they are ready and waiting for the next time that there is exposure to the mold spore. This stage is when the body is said to be sensitized.

The Allergic Reaction
At the next exposure, the antibody from the immune system is ready and marks the mold spore for destruction. This action activates the process of degranulation of the mast cells. This means that the mast cells burst open and releases over 30 inflammatory chemicals. Histamine in one of the chemicals released. These inflammatory chemicals are the body’s defense mechanism to stop harmful foreign particles from entering and invading the body. It is these chemicals that are released from the mast cells that actually cause the symptoms of mold allergy.

Symptoms

Inflammatory chemicals released by the mast cells are designed to prevent the allergen from entering into the body. This is done by causing nasal congestion. These chemicals will also try to make the body expel the allergen that has already entered. Thus, these chemicals will cause sneezing or watery eyes to flush out the allergen. Symptoms caused by mold allergies will be basically the same as they are with other airborne allergens. Mold spores will have an effect on the upper respiratory tract, the eyes, and the nose. The main symptoms caused by mold allergies are;

• sneezing
• runny and itchy nose
• red and itchy eyes
• headaches
• post nasal drip
• nasal congestion
• sinusitis

People who have asthma and mold allergies can experience an aggravation to their asthma. The small particle size of the mold spore can sometimes travel deeper inside the body. Increase coughing, shortness of breath, and wheezing can also be symptoms. If you are increasing your usage of asthma medication for no apparent reason, you should consult with your physician to see what else you might be allergic to.

Risk Factors

Genetics
It is not known for sure why some people develop a mold allergy and others do not. It is believed that genetics play a role. If a parent has allergies, there is a possibility of the child developing allergies. The likelihood of the child developing allergies increases if both parents have allergies. It is not a specific allergy that you inherit. It is only the likelihood of developing allergies that you inherit. The parent can be allergic to one allergen and the child can be allergic to another.

Environment
The environment of an individual, particularly while they are young, seems to play a role. One theory in the medical community is that if you were exposed to a lot of mold at a very young age, your chances of developing mold allergy increases. This likelihood of developing mold allergy increases also with exposure to airborne irritants such as second hand smoke, air pollution, poor indoor air quality, and strong fumes. With today’s homes being built more draft-proof, exposure is for a longer period of time. It is possible for this to stimulate the immune system to produce IgE antibodies with so many foreign particles entering the body.

Mold Season

There are no particular dates on the calendar that can be labeled “mold allergy season.” Unlike pollen allergy, mold growth has a closer relationship with weather and humidity. Pollen producing plants (trees, grasses, and weeds) grow outdoors and have their growth cycle in nature. Mold, on the other hand, grows both indoors and outdoors and grows all year long.

Outdoor Mold
Mold allergy season outdoors depends on the climate in which you live. If you live in an area where there is never a hard freeze, fungi can grow outdoors year-round. If you live in a geographic location where nature provides hard freezes, some fungi may die but many other species may just go dormant. Either way, mold begins to grow in the spring. After winter, there is plenty of organic matter for mold to feed on. Spring showers provide the ideal environment for mold to thrive.

Summer tends to be a time when mold spores are not at their peak. Most geographic locations have warm summers with not a lot of rain. To thrive and reproduce, fungi need the moisture. On the other hand, there are so many different species of fungi and some species do prefer to release their spores during dry and windy weather. Generally speaking, late summer into fall is when most people are affected. There is plenty of dying organic matter to feed on and the cooler temperatures provide adequate dampness. This can be a particularly difficult time for people with hay fever since ragweed is also at its peak at this time.

Indoor Mold
Indoor mold tends to grow better in the winter. Fewer windows are open and the house is aired out less. Moisture from showers and cooking and other household activities is trapped in by the house better in the winter than in the summer. This can be a particularly difficult time for those who suffer from perennial allergic rhinitis. Pet allergy and dust mite allergy also peak indoors during winter when the house is closed up tight. With the cooler temperatures and the humidity trapped inside, the moisture lingers in the house longer. This provides the ideal environment for mold and dust mites to thrive.

The above is a picture of Curvularia geniculata which is normally found in soil and decaying vegetation. Taken with a scanning electron microscope (SEM, it shows the organism’s hyphae and conidiophores topped with spore-containing conidia.

Testing

When the immune system produces IgE antibodies to protect itself, the antibodies are very specific. These proteins match whatever it is fighting. For this reason, it is very easy for doctors to test for these antibodies and they will tell the physician what you are allergic to.

Although a blood test can be performed to test for IgE antibodies, a skin test is the easiest and most cost effective way of finding out what you are allergic to. A blood test is usually performed when the patient has a skin condition that would not allow a skin test to be performed.

When a skin test is performed, a weaken extract of the suspected allergen is placed on the skin. It is scratched into the skin using a special kind of needle. Another way of doing this is by injecting the purified allergen extract under the skin.

A positive reaction will result in the skin getting red and a bump developing at the test site. To interpret the results correctly requires a trained and experienced allergist. Sometimes these tests can yield false results or be interpreted incorrectly.

Avoidance

With mold allergy, avoiding the mold spore is next to impossible. On the other hand, there is a lot of mold allergy avoidance tips that will help you find that you can manage your allergy and bring it under control. There are many natural and non-invasive things that you can do that can bring you relief and improved health. You may not be able to avoid the mold spores, however, there are many things that you can do that will result in having less mold allergy symptoms.

Getting to know and to learn more about mold will enhance your battle against mold allergy symptoms. If you know what environment mold thrives in, you’ll know how to eliminate those conditions in your home.

To learn more, read the article Mold Allergy by the Asthma and Allergy Foundation of America.

Go to the nasal allergies home page.

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