What is mold allergy

Mold is a visible group of fungi that forms and spreads on various kinds of damp or decaying organic matter, such as dry wall and other building materials. Molds can be found outdoors, in homes and in other buildings. There are many different types of mold, with some 1.5 million species estimated to exist. Some people may refer to mold as mildew. Both are terms used to describe fungal growth. Mildew is typically powdery and light in color, whereas mold is often fuzzy and more colorful.

Molds like damp environments and need four things to grow:

1. food,
2. air,
3. appropriate temperature and
4. water.

Molds spores can float through the air. Everyone breathes in mold spores in the air, but some people have an allergic reaction or asthma symptoms if exposed to too much of this fungus.

If you are allergic to mold, your immune system is overly-sensitive to specific mold spores and treats them as an allergen. When you inhale the mold spores, your immune system triggers symptoms such as sneezing, itchy, watery eyes, runny nose, nasal congestion or itchy nose, mouth and lips.

There are hundreds of types of molds, but not all of them are responsible for causing allergy symptoms.

The most common allergy-causing molds include:

• Alternaria,
• Aspergillus,
• Cladosporium and
• Penicillium.

How do people get exposed to mold?

People are exposed to molds every day and everywhere, at home, at work, at school, both indoors and out. Molds are generally not harmful to healthy humans.
Inhalation is considered the primary way that people are exposed to mold. Mold spores and fragments can become airborne and get into the air we breathe. People may also be exposed to mold through the skin. Workers should be properly protected with safety equipment when remediating or cleaning up mold after a disaster. In some cases, people may be exposed to mold through their diet.

It is well established that allergic reactions to molds are the most commonly experienced health effects in humans ¹. Symptoms can range from sneezing to wheezing. Individuals without allergies may also experience symptoms, including eye irritation, sore throat, congestion, skin rash, and headaches.

Figure 1. Mold allergy rash

Mold allergy signs and symptoms

Many people allergic to mold develop symptoms outdoors on days when mold spores are in the air. You may also have symptoms indoors if mold is in your home, school or workplace.

Symptoms of mold allergy include:

• Itchy nose, mouth and lips
• Sneezing
• Wheezing
• Itchy, watery eyes
• Runny nose
• Nasal congestion
• Dry, scaly skin

Mold can also trigger asthma symptoms such as wheezing, shortness of breath or chest tightness.

Mold allergy symptoms vary from person to person and range from mild to severe. You may have year-round symptoms or symptoms that flare up only during certain times of the year. You may notice symptoms when the weather is damp or when you’re in indoor or outdoor spaces that have high concentrations of mold.

Mold allergy and asthma

If you have a mold allergy and asthma, your asthma symptoms may be triggered by exposure to mold spores. In some people, exposure to certain molds can cause a severe asthma attack. Signs and symptoms of asthma include:

• Coughing
• Wheezing
• Shortness of breath
• Chest tightness

Causes of mold allergy

Like any allergy, mold allergy symptoms are triggered by an overly sensitive immune system response. When you inhale tiny, airborne mold spores, your body recognizes them as foreign invaders and develops allergy-causing antibodies to fight them.

After the exposure has passed, you still produce antibodies that “remember” this invader so that any later contact with the mold causes your immune system to react. This reaction triggers the release of substances such as histamine, which cause itchy, watery eyes, runny nose, sneezing and other mold allergy symptoms.

Molds are very common both inside and outside. There are many types, but only certain kinds of mold cause allergies. Being allergic to one type of mold doesn’t necessarily mean you’ll be allergic to another. Some of the most common molds that cause allergies include alternaria, aspergillus, cladosporium and penicillium.

Risk factors for mold allergy

A number of factors can make you more likely to develop a mold allergy or worsen your existing mold allergy symptoms, including:

• Having a family history of allergies. If allergies and asthma run in your family, you’re more likely to develop a mold allergy.

• Working in an occupation that exposes you to mold. Occupations where mold exposure may be high include farming, dairy work, logging, baking, millwork, carpentry, greenhouse work, winemaking and furniture repair.

• Living in a house with high humidity. If your indoor humidity is higher than 50 percent, you may have increased exposure to mold in your home. Mold can grow virtually anywhere if the conditions are right — in basements, behind walls in framing, on soap-coated grout and other damp surfaces, in carpet pads, and in the carpet itself. Exposure to high levels of household mold may trigger mold allergy symptoms.

• Working or living in a building that’s been exposed to excess moisture. Examples include leaky pipes, water seepage during rainstorms and flood damage. At some point, nearly every building has some kind of excessive moisture. This moisture can allow mold to flourish.
  Living in a house with poor ventilation. Tight window and door seals may trap moisture indoors and prevent proper ventilation, creating ideal conditions for mold growth. Damp areas — such as bathrooms, kitchens and basements — are most vulnerable.

Complications of mold allergy

Most allergic responses to mold involve hay fever-type symptoms that can make you miserable but aren’t serious. However, certain allergic conditions caused by mold are more severe. These include:

• Mold-induced asthma. In people allergic to mold, breathing in spores can trigger an asthma flare-up. If you have a mold allergy and asthma, be sure you have an emergency plan in place in case of a severe asthma attack.
• Allergic fungal sinusitis. This results from an inflammatory reaction to fungus in the sinuses.
• Allergic bronchopulmonary aspergillosis. This reaction to fungus in the lungs can occur in people with asthma or cystic fibrosis.
• Hypersensitivity pneumonitis. This rare condition occurs when exposure to airborne particles such as mold spores causes the lungs to become inflamed. It may be triggered by exposure to allergy-causing dust at work.

Other problems caused by mold

Besides allergens, mold may pose other health risks to susceptible people. For example, mold may cause infections of the skin or mucous membranes. Generally, however, mold doesn’t cause systemic infections except for people with impaired immune systems, such as those who have HIV/AIDS or who are taking immunosuppressant medication.

Prevention of mold allergy

To reduce mold growth in your home, consider these tips:

• Eliminate sources of dampness in basements, such as pipe leaks or groundwater seepage.
• Use a dehumidifier in any area of your home that smells musty or damp. Keep your humidity levels below 50 percent. Remember to clean the collection bucket and condensation coils regularly.
• Use an air conditioner, and consider installing central air conditioning with a high-efficiency particulate air (HEPA) filter attachment. The HEPA filter can trap mold spores from outdoor air before they’re circulated inside your home.
• Change filters on your furnace and air conditioners regularly. Have forced air heating ducts inspected and, if necessary, cleaned.
• Be sure all bathrooms are properly ventilated, and run the ventilation fan during a shower or bath and immediately after to dry the air. If you don’t have a ventilation fan, open a window or door while you’re showering or bathing.
• Don’t carpet bathrooms and basements.
• Promote groundwater drainage away from your house by removing leaves and vegetation from around the foundation and cleaning out rain gutters frequently.
• Keep organic plant containers clean and dry, such as those made of straw, wicker or hemp.
• Toss or recycle old books and newspapers. If left in damp places, such as basements, they can quickly become moldy.

Mold allergy test

Symptoms of mold allergy often mimic symptoms of other conditions. An allergist / immunologist can diagnose whether mold is responsible for your symptoms.

Skin prick tests give accurate results in just a few minutes. Your allergist may order other tests, if needed.

Skin allergy testing is the most common, reliable and relatively painless form of allergy testing. A very small amount of certain allergens is put into your skin by making a small indentation or “prick” on the surface of your skin in your arm or back. A skin allergy test determines specific allergens based on skin reactions. You don’t have to wait long to find out what is triggering your allergies. Reactions occur within about 15 minutes.

If you have allergies, just a little swelling (hive) will occur where the allergen(s) which you are allergic to was introduced. For instance, if you are allergic to black mold but not to cats, only the black mold allergen will cause a little swelling or itching. The spot where the cat allergen was applied will remain normal.

Blood test. A blood test, sometimes called the radioallergosorbent test, can measure your immune system’s response to mold by measuring the amount of certain antibodies in your bloodstream known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to specific types of mold.

Mold allergy treatment

If you have a mold allergy, avoiding exposure to the allergen is the best way to manage your symptoms. Avoidance tips include:

• Stay indoors on days when mold counts are high.
• Keep away from uncut fields and avoid raking leaves.
• Take a shower after coming indoors. This will wash out mold spores in your hair to keep them from bothering you all night long.
• Eliminate mold from your home by fixing leaking faucets and pipes.
• Reduce the humidity in your home. Be sure your indoor humidity stays below 60 percent.
• Remove basement carpeting and replace with linoleum or concrete flooring that will not retain moisture.
• Clean mold off walls using a vinegar solution.

In addition to managing symptoms by avoidance, your allergist may also recommend treating your symptoms with over-the-counter or prescription antihistamines, eye drops or nasal sprays.

While there’s no sure way to cure allergic rhinitis caused by a mold allergy, a number of medications can ease your symptoms. These include:

• Immunotherapy (allergy shots) are a form of treatment that provides long-term relief of symptoms. Your allergist will give you shots containing small doses of your allergen, allowing your body to build a natural immunity to the trigger.

• Nasal lavage. To help with irritating nasal symptoms, your doctor may recommend that you rinse your nose daily with salt water. Use a specially designed squeeze bottle, such as the one included in saline kits (Sinus Rinse, others), bulb syringe or neti pot to irrigate your nasal passages. This home remedy, called nasal lavage, can help keep your nose free of irritants. Use water that’s distilled, sterile, previously boiled and cooled, or filtered using a filter with an absolute pore size of 1 micron or smaller to make up the irrigation solution. Also be sure to rinse the irrigation device after each use with similarly distilled, sterile, previously boiled and cooled, or filtered water and leave open to air-dry.

• Nasal corticosteroids. These nasal sprays help prevent and treat the inflammation caused by an upper respiratory mold allergy. For many people, they’re the most effective allergy medications, and they’re often the first medication prescribed. Examples include ciclesonide (Omnaris), fluticasone (Flonase), mometasone (Nasonex), triamcinolone (Nasacort AQ) and budesonide (Rhinocort Aqua). Nosebleeds and nasal dryness are the most common side effects of these medications, which are generally safe for long-term use.

• Antihistamines. These medications can help with itching, sneezing and runny nose. They work by blocking histamine, an inflammatory chemical released by your immune system during an allergic reaction. Over-the-counter (OTC) antihistamines include loratadine (Alavert, Claritin), fexofenadine (Allegra) and cetirizine (Zyrtec Allergy). They cause little to no drowsiness or dry mouth. Older antihistamines such as clemastine (Tavist-1) work as well but can make you drowsy, affect work and school performance, and cause dry mouth.

• The nasal sprays azelastine (Astelin, Astepro) and olopatadine (Patanase) are available by prescription. Side effects of the nasal sprays may include a bitter taste in your mouth and nasal dryness.

• Oral decongestants. OTC oral decongestants include Sudafed and Drixoral. Because oral decongestants can raise blood pressure, avoid them if you have high blood pressure (hypertension). Possible side effects include high blood pressure, insomnia, loss of appetite, heart pounding (palpitations), anxiety and restlessness.
• Decongestant nasal sprays. These include oxymetazoline (Afrin, others). Don’t use these medications for more than three or four days, as they can cause congestion to come back with even worse symptoms when you stop using them. Other possible side effects include headache, insomnia and nervousness.

• Montelukast. Montelukast (Singulair) is a tablet taken to block the action of leukotrienes — immune system chemicals that cause allergy symptoms such as excess mucus. It has proved effective in treating allergic asthma, and it’s also effective in treating mold allergy.

Like antihistamines, this medication is not as effective as inhaled corticosteroids. It’s often used when nasal sprays cannot be tolerated or when mild asthma is present.

Lifestyle and home remedies

To keep mold allergy symptoms at bay, take these measures:

• Sleep with your windows closed to keep out outdoor mold. The concentration of airborne mold spores tends to be greatest at night, when the weather is cool and damp.
• Wear a dust mask over your nose and mouth to keep mold spores out if you have to rake leaves, mow your lawn or work around compost.
• Avoid going outdoors at certain times, such as immediately after a rainstorm, in foggy or damp weather, or when the published mold count is high.

1. Storey E, Dangman KH, Schenck P, DeBernardo RL, Yang CS, Bracker A, Hodgson MJ. 2004. Guidance for clinicians on the recognition and management of health effects related to mold exposure and moisture indoors.[↩]