What are the symptoms of mold allergy

Inhalation exposure to mold indoors can cause health effects in some people. Molds produce:

  1. Irritants
  2. Allergens (substances that can cause allergic reactions)
  3. Potentially toxic substances or chemicals (mycotoxins)

Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Mold does not own to be alive to cause an allergic reaction. Dead or alive, mold can cause allergic reactions in some people.

Other Health Effects

Breathing in mold may also cause hypersensitivity pneumonitis, an unusual disease that resembles bacterial pneumonia. In addition, mold exposure may result in opportunistic infections in persons whose immune systems are weakened or suppressed.

When mold grows indoors, the occupants of a building may start to report odors and a variety of symptoms including:

  1. Allergic reactions
  2. Difficulty breathing
  3. Skin irritation
  4. Headaches
  5. Aggravated asthma symptoms

These and other symptoms may be associated with exposure to mold.

But every of these symptoms may be caused by other exposures or conditions unrelated to mold growth. Therefore, it is significant not to assume that, whenever any of these symptoms occurs, mold is the cause.

For more detailed information on mold and its health effects, consult:

Allergic Reactions, Asthma Attacks, Irritant Effects

Allergic reactions to mold are common and can be immediate or delayed. Repeated or single exposure to mold, mold spores, or mold fragments may cause non-sensitive individuals to become sensitive to mold, and repeated exposure has the potential to increase sensitivity.

Allergic responses include hay fever-like symptoms such as:

  1. Red eyes
  2. Sneezing
  3. Runny nose
  4. Headache
  5. Skin rash (dermatitis)

Molds can cause asthma attacks in people with asthma who are allergic to mold. In addition, whether or not individuals are allergic to mold, molds can irritate:

  1. Throat
  2. Skin
  3. Nose
  4. Eyes
  5. Lungs

Damp Buildings

Although mold is frequently found in damp buildings, it is not the only potential contaminant — biological contaminants other than mold, and non-biological contaminants are often present and may also cause health effects.

Damp buildings may attract rodents and other pests. Damp or wet building components and furnishings may release chemicals indoors.

Potential contaminants in damp or wet buildings include:

  1. Cockroaches and other pests
  2. Dust mites
  3. Bacteria
  4. Chemicals emitted by damp building materials and furnishings

For more information on damp buildings and health effects, see the 2004 Institute of Medicine Report, Damp Indoor Spaces and Health, published by The National Academies Press.

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Asthma and Mold

The following links are to non-federal government sites Exit

Molds can trigger asthma episodes in sensitive individuals with asthma.

People with asthma should avoid contact with or exposure to molds.

What are the symptoms of mold allergy

Read more about asthma triggers on EPA’s Asthma Website

Additional Asthma Resources:

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Learn more about mold and health effects in a «A Brief Guide to Mold, Moisture and Your Home»

The entire booklet:

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Introduction to Molds

  • Moldy Smell
  • Health Effects That May Be Caused by Inhaling Mold or Mold Spores
  • Mycotoxins and Health Effects
  • What Mold Needs to Grow
  • The Color of Mold
  • What Molds Are
  • Biocides

Lesson 2 — What Mold Needs to Grow

To grow indoors, mold needs moisture and food.

Moisture is the most significant factor influencing mold growth indoors. Controlling indoor moisture helps limit mold growth.

Moisture control is the key to mold control.


Mold does not need a lot of water to grow. A little condensation, in a bathroom or around a window sill, for example, can be enough. Common sites for indoor mold growth include:

  1. Near leaky water fountains
  2. Basement walls
  3. Areas around windows
  4. Bathroom tile and grout
  5. Around sinks

Common sources of water or moisture include:

  1. Sprinkler systems
  2. Slow leaks in plumbing fixtures
  3. Condensation due to high humidity or freezing spots in a building
  4. Roof leaks
  5. Humidification systems
  6. Floods


Besides moisture, mold needs nutrients, or food, to grow.

Mold can grow on virtually any organic substance. Most buildings are full of organic materials that mold can use as food, including:

  1. Plant material
  2. Cloth
  3. Wood
  4. Paper
  5. Soil

In most cases, temperature is not an issue; some molds grow in warm areas, while others prefer cool locations such as bread stored in a refrigerator. Often, more than one type of mold can be found growing in the same area, although conditions such as moisture, light and temperature may favor one species of mold over another.

Buildings that own been heavily damaged by flood waters should be assessed for structural integrity and remediated by experienced professionals.

Please note that the guidelines covered in this course were developed for damage caused by clean water (not flood water, sewage, or other contaminated water).

For more information see:

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Mold Allergy

How Do Doctors Diagnose Mold Allergy?

To diagnose an allergy to mold or fungi, the doctor will take a finish medical history. If they suspect a mold allergy, the doctor often will do skin tests or allergen specific IgE blood tests.

Extracts of diverse types of fungi may be used to scratch or prick the skin. If there is no reaction, then you probably don’t own an allergy. The doctor uses the patient’s medical history, the skin testing results and the physical exam to diagnose a mold allergy.

How Can I Prevent an Allergic Reaction to Mold?

There is no cure for allergies. But you can reduce your allergy symptoms by avoiding contact with the mold spores. Several measures will help:

Reduce Your Exposure to Mold Spores Outside

  1. Limit your outdoor activities when mold counts are high.

    This will lessen the quantity of mold spores you inhale and your symptoms.

  2. Wear a dust mask when cutting grass, digging around plants, picking up leaves and disturbing other plant materials.

Reduce Your Exposure to Mold Spores Inside

  1. Lower your indoor humidity. No air cleaners will assist if excess moisture remains.

    What are the symptoms of mold allergy

    If indoor humidity is above 50%, fungi will thrive. A hygrometer is a tool used to measure humidity. The goal is to hold humidity under 45%, but under 35% is better.

    If you own to use a humidifier, clean the fluid reservoir at least twice a week to prevent mold growth.

    What are the symptoms of mold allergy

    Air conditioners and dehumidifiers can also be a source of mold.

  2. Use central air conditioning with a CERTIFIED asthma & allergy friendly® filter attachment. This can assist trap mold spores from your entire home. Freestanding air cleaners only filter air in a limited area. Avoid devices that treat air with heat, electrostatic ions or ozone.
  3. Prevent mold and mildew build up inside the home. Pay shut attention to mold in bathrooms, basements and laundry areas. Be aggressive about reducing dampness.

To Reduce Mold in Your Bathrooms:

  1. Scour sinks and tubs at least monthly.

    Fungi thrive on soap and other films that jacket tiles and grout.

  2. Remove bathroom carpeting from places where it can get wet.
  3. Use an exhaust fan or open a window in the bathroom during baths and showers.
  4. Quickly repair any plumbing leaks.

To Reduce Mold in Your Kitchen:

  1. Quickly repair any plumbing leaks.
  2. Clean refrigerator door gaskets and drip pans.
  3. Clean trash pails frequently.
  4. Use an exhaust fan when you are cooking or washing dishes.

To Reduce Mold in Your Laundry Area:

  1. Don’t leave wet, damp clothes sitting around.
  2. If you own a front-loading washing machine, clean the rubber seal and inside of the door.

    Leave the door cracked open when the machine is not in use.

  3. Remove clothes from washing machine promptly.
  4. Make certain your laundry area has excellent air circulation.

To Reduce Mold in Your Bedrooms:

  1. Check windows for condensation (water droplets or mist).
  2. Throw away or recycle ancient books, newspapers, clothing or bedding.
  3. Polyurethane and rubber foams seem especially prone to fungus invasion. Use plastic covers on bedding made from these foams.
  4. Improve air flow through your bedroom. If your closet is colder than the relax of your room, leave the closet doors open.

To Reduce Mold in Your Basement:

  1. Quickly repair any plumbing leaks.
  2. Promote ground water drainage away from a home.

    Remove leaves and dead vegetation near the foundation and in the rain gutters.

To Reduce Mold in Your Whole House:

  1. Increase air flow in your home. Open doors between rooms, move furniture away from walls and use fans if needed.
  2. Use an electric dehumidifier to remove moisture and hold humidity in your home under 45 percent.

    What are the symptoms of mold allergy

    Drain the dehumidifier regularly and clean the condensation coils and collection bucket.

  3. Repair roof leaks and roof gutters. Clean out your gutters to remove leaves and debris. When gutters are full or damaged, it can cause leaking.

What Is a Mold Allergy?

If you own an allergy that occurs over several seasons, you may be allergic to the spores of molds or other fungi. Molds live everywhere. Upsetting a mold source can send the spores into the air.

Mold and mildew are fungi.

They are diverse from plants or animals in how they reproduce and grow. The “seeds,” called spores, travel through the air. Some spores spread in dry, windy weather. Others spread with the fog or dew when humidity is high.

Inhaling the spores causes allergic reactions in some people. Allergic symptoms from fungus spores are most common from July to early drop. But fungi grow in numerous places, both indoors and exterior, so allergic reactions can happen year round.

Although there are numerous types of molds, only a few dozen cause allergic reactions.

Numerous molds grow on rotting logs and fallen leaves, in compost piles and on grasses and grains. Unlike pollens, molds do not die with the first killing frost. Most outdoor molds become inactive during the winter. In the spring they grow on plants killed by the freezing. Indoors, fungi grow in damp areas. They can often be found in the bathroom, kitchen or basement.

What Are the Symptoms of a Mold Allergy?

The symptoms of mold allergy are extremely similar to the symptoms of other allergies, such as sneezing, itching, runny nose, congestion and dry, scaling skin.

  1. Outdoor molds may cause allergy symptoms in summer and drop (or year-round in some climates)
  2. Indoor molds may cause allergy symptoms year-round

Mold spores get into your nose and cause hay fever symptoms.

They also can reach the lungs and trigger asthma. A chemical released by allergy cells in the nose and or lungs causes the symptoms. Sometimes the reaction happens correct away. Sometimes a mold allergy can cause delayed symptoms, leading to nasal congestion or worsening asthma over time. Symptoms often get worse in a damp or moldy room love a basement. This may mean you own a mold allergy.

Rarely, some patients can own a more serious illness called allergic bronchopulmonary aspergillosis. In this condition, there is both an allergic and an inflammatory response to the mold. Symptoms may include severe wheezing, coughing and shortness of breath, much love asthma.

Food fungi, love mushrooms, dried fruit, or foods containing yeast, vinegar or soy sauce, generally don’t cause allergy symptoms of the nose, eyes and lungs.

It is more likely that reactions to food fungi are caused by the food’s direct effect on blood vessels. For example, fermented foods (like wine) may naturally contain a substance known as histamine. Histamine is also a chemical your allergy cells release during an allergic reaction. Foods that contain histamines can trigger allergy-like responses when you consume them.

What Are the Treatments for Mold Allergy?

In some cases, there may be ways to reduce or remove mold exposure. This may not always be possible and you may need medications.

  1. Avoid contact with mold.

    (See tips above)

  2. Take medications for nasal or other allergic symptoms. Antihistamines and nasal steroids are available over the counter without a prescription. If you own allergic asthma, talk to your doctor about which medicines may be best for you.

    What are the symptoms of mold allergy

    You might also be a candidate for allergy shots. Allergy shots may assist reduce symptoms and medications. Study more about allergy treatments.

Medical Review October 2015.

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How do molds affect people?

Molds are generally not a problem indoors, unless mold spores land on a wet or damp spot and start growing. Molds own the potential to cause health problems. Molds produce allergens (substances that can cause allergic reactions) and irritants. Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash.

Allergic reactions to mold are common.

They can be immediate or delayed. Molds can also cause asthma attacks in people with asthma who are allergic to mold. In addition, mold exposure can irritate the eyes, skin, nose, throat, and lungs of both mold-allergic and non-allergic people. Symptoms other than the allergic and irritant types are not commonly reported as a result of inhaling mold. Research on mold and health effects is ongoing.

The above does not describe every potential health effects related to mold exposure. For more detailed information consult a health professional, your state or local health department, or the Centers for Disease Control and Prevention mold website.

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Lesson 4 — Mycotoxins and Health Effects

As molds grow, some (but not all) of them may produce potentially toxic byproducts called mycotoxins under some conditions.

Some of these molds are commonly found in moisture-damaged buildings. More than 200 mycotoxins from common molds own been identified, and numerous more remain to be identified. The quantity and types of mycotoxins produced by a specific mold depends on numerous environmental and genetic factors.

What are the symptoms of mold allergy

No one can tell whether a mold is producing mycotoxins just by looking at it.

Some mycotoxins are known to affect people, but for numerous mycotoxins little health information is available. Research on mycotoxins is ongoing.

What are the symptoms of mold allergy

Exposure to mycotoxins can happen from inhalation, ingestion and skin contact. It is prudent to avoid unnecessary inhalation exposure to mold.

For more information on mycotoxins, see the 2004 Institute of Medicine Report, Damp Indoor Spaces and Health, published by The National Academies Press in Washington, DC.

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Lesson 1 — What Molds Are

Partially decomposed beech leaf.

Molds are organisms that may be found indoors and outdoors. They are part of the natural environment and frolic an significant role in the environment by breaking below and digesting organic material, such as dead leaves.

Also called fungi or mildew, molds are neither plants nor animals; they are part of the kingdom Fungi.

Magnified mold and mold spores

Molds can multiply by producing microscopic spores (2 — 100 microns [µm] in diameter), similar to the seeds produced by plants. Numerous spores are so little they easily float through the air and can be carried for grand distances by even the gentlest breezes. The number of mold spores suspended in indoor and outdoor air fluctuates from season to season, day to day and even hour to hour.

Mold spores are ubiquitous; they are found both indoors and outdoors.

Mold spores cannot be eliminated from indoor environments. Some mold spores will be found floating through the air and in settled dust; however, they will not grow if moisture is not present.

Mold is not generally a problem indoors — unless mold spores land on a wet or damp spot and start growing. As molds grow they digest whatever they are growing on. Unchecked mold growth can:

  1. Cause structural damage to buildings
  2. Rot wood
  3. Damage drywall
  4. Damage buildings and furnishings
  5. Cause cosmetic damage, such as stains, to furnishings

The potential human health effects of mold are also a concern.

It is significant, therefore, to prevent mold from growing indoors.

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