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Mold allergy

Medically reviewed by Drugs.com. Last updated on Jun 21, 2021.

Overview

If you have a mold allergy, your immune system overreacts when you breathe in mold spores. A mold allergy can cause coughing, itchy eyes and other symptoms that make you miserable. In some people, a mold allergy is linked to asthma and exposure causes restricted breathing and other airway symptoms.

If you have a mold allergy, the best defense is to reduce your exposure to the types of mold that cause your reaction. Medications can help keep mold allergy reactions under control.

Symptoms

A mold allergy causes the same signs and symptoms that occur in other types of upper respiratory allergies. Signs and symptoms of allergic rhinitis caused by a mold allergy can include:

  • Sneezing
  • Runny or stuffy nose
  • Cough and postnasal drip
  • Itchy eyes, nose and throat
  • Watery eyes
  • Dry, scaly skin
  • Mold allergy symptoms vary from person to person and range from mild to severe. You might have year-round symptoms or symptoms that flare up only during certain times of the year. You might 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 can 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

    When to see a doctor

    If you have a stuffy nose, sneezing, watery eyes, shortness of breath, wheezing or other bothersome symptoms that persist, see your doctor.

    Causes

    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.

    Exposure to mold spores can cause a reaction right away, or the reaction can be delayed.

    Various molds are common indoors and outdoors. Only certain kinds of mold cause allergies. Being allergic to one type of mold doesn't mean you'll be allergic to another. Some of the most common molds that cause allergies include alternaria, aspergillus, cladosporium and penicillium.

    Risk factors

    A number of factors can make you more likely to develop a mold allergy or worsen your 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 can be high include farming, dairy work, logging, baking, millwork, carpentry, greenhouse work, winemaking and furniture repair.
    • Living in a house with high humidity. Having indoor humidity higher than 50% can increase 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 can 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, which can encourage mold growth.
    • Living in a house with poor ventilation. Tight window and door seals can 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

    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 that you have an emergency plan 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 lung inflammation. It can be triggered by exposure to allergy-causing dust at work.

    Other problems caused by mold

    Besides allergens, mold can pose other health risks to susceptible people. For example, mold can 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

    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%. 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. Make sure the ground slopes away from the foundation.
    • 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.

    Diagnosis

    Besides considering your signs and symptoms, your doctor might conduct a physical examination to identify or exclude other medical problems. Tests used to identify an allergy include:

    • Skin prick test. This test uses diluted amounts of common or suspected allergens, such as molds found in the local area. During the test, these substances are applied to the skin of your arm or back with tiny punctures. If you're allergic, you develop a raised bump (hive) at the test location on your skin.
    • 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.
    Positive reaction to allergy test

    A small area of swelling with surrounding redness is typical of a positive patch skin test for allergy.

    Treatment

    The best way to manage an allergy is to avoid exposure to triggers. However, molds are common, and you can't completely avoid them.

    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:

    • 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, Zetonna), fluticasone (Flonase Allergy Relief, Xhance), mometasone (Nasonex), triamcinolone and budesonide (Rhinocort). 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 Allergy) and cetirizine (Zyrtec Allergy). They cause little to no drowsiness or dry mouth.

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

    • Oral decongestants. OTC oral decongestants, such as Sudafed 12 Hour and Drixoral Cold and Allergy, can raise blood pressure, so avoid them if you have high blood pressure (hypertension). Other possible side effects include 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 worse symptoms when you stop using them. Other possible side effects include headaches, 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. However, concerns about side effects, including anxiety, insomnia, depression and suicidal thinking, are increasing. The U.S. Food and Drug Administration recently put a warning on the box about the drug's use.

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

    Other treatments for mold allergy include:

    • Immunotherapy. This treatment — a series of allergy shots — can be very effective for some allergies, such as hay fever. Allergy shots are used for only certain types of mold allergy.
    • Nasal lavage. To help with irritating nasal symptoms, your doctor might 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. 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.

    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.
    • Keep indoor humidity below 50% and correct any moisture or water damage in the home. You can measure relative humidity with a small moisture meter, available at many hardware stores.
    • 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.

    Preparing for an appointment

    Many people are diagnosed and treated for allergies by their primary care physicians. However, depending on the severity of your allergies, your primary care doctor might refer you to a doctor who specializes in treating allergies.

    Here's some information to help you get ready for your appointment.

    What you can do

    • Ask if there are any pre-appointment restrictions when making your appointment. For example, if you're having allergy tests, your doctor will likely want you to stop taking allergy medications for several days before the test.
    • Write down your symptoms, as well as where you were and what you were doing when the symptoms started.
    • List all the medications, vitamins or other supplements you take, including doses.
    • Write down questions for your doctor.

    For a mold allergy, some questions you might want to ask include:

    • What do you think is causing these symptoms?
    • Are there tests available that can confirm a specific allergy? Do I need to prepare for these tests?
    • How can I treat a mold allergy?
    • What side effects can I expect from allergy medications?
    • How can I get mold out of my home?
    • I have another health condition. How can I best manage these conditions together?
    • Do you have brochures or other printed materials I can have? What websites do you recommend?

    What to expect from your doctor

    Your doctor is likely to ask you questions, such as:

    • Exactly what are your symptoms?
    • What seems to trigger symptoms or worsen them?
    • Are your symptoms worse during certain times of the year or certain times of the day?
    • Do your symptoms flare up when you're in certain locations, such as outdoors or in your basement?
    • What other health problems do you have?
    • Do other members of your family have allergies? What kinds?
    • Are you exposed to mold, dust, fumes or chemicals at work?
    • Do you know if you have mold in your home?

    What you can do in the meantime

    While you're waiting to see your doctor, there are numerous over-the-counter allergy medications that may ease your symptoms.

    If you have visible mold in your home, have someone who's not allergic to mold clean the area using a solution of 1 cup (250 ml) of bleach to 1 gallon (3.8 liters) of water or a commercially available mold-cleaning product. If you have to clean up the mold yourself, be sure to wear long rubber gloves, safety goggles and a mask to limit your exposure to the mold.

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