Mold Allergy: Signs, Diagnosis, Prevention, and Relief


Can mold cause allergies?

Mold can cause allergies in people who touch or inhale mold spores. People with mold allergy may experience symptoms such as wheezing, shortness of breath, and coughing when they are exposed to mold. Exposure can also lead to nose, eye, and sinus irritation in people without mold allergies.

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What Is a Mold Allergy?

Mold refers to fungal growths that form and grow on damp and decaying matter. They grow both indoors and outdoors in most climates year-round. When they are either touched or inhaled, spores from these fungal growths can trigger an immune system response, causing a variety of symptoms.  

What Causes an Allergy to Mold?

Mold allergies are caused by an overreaction in the immune system when exposed to mold spores. The immune system identifies mold spores as a threat to the body and develops antibodies to fight off the allergens, causing inflammation and allergy symptoms.

Although there are up to 1,000 species of mold in the US, most of them will not cause allergic reactions. Developing a mold allergy greatly depends on the type of mold, the strength of your immune system, and the level of exposure.

Exposure to Certain Types of Mold

Coming into contact with the following types of mold will increase your chances of developing mold allergy:

Immune System Sensitivity

Mold allergies primarily occur when the immune system mistakenly classifies mold spores as outside invaders and begins churning out antibodies to fight them. One side effect of these antibodies is that they also cause allergy symptoms. Your odds of developing a mold allergy may be higher if you have an overactive immune system.

Level of Exposure to Mold

Some people are more sensitive to mold spores while others have conditions such as asthma and pre-existing allergies that increase their likelihood of having allergy symptoms upon mold exposure. However, the severity of mold allergy symptoms depends on the level of mold exposure. The more mold spores you come in contact with, the more severe your symptoms will likely be.

Mold Allergy Symptoms

Many of the symptoms of mold allergies are similar to the symptoms caused by other respiratory allergies. They include;

  • Wheezing
  • Chest tightness
  • Shortness of breath
  • Nasal congestion
  • Runny nose
  • Itchy, watery eyes
  • Itchy mouth, lips, and nose
  • Coughing
  • Sneezing
  • Skin rashes
  • Headaches

Types of Mold Allergies

Most types of mold allergies that affect people stem from a small group of molds. You may be allergic to one type of mold but unreactive to other types. The following are the main types of mold allergies:


This type of mold is identifiable by its musty, earthy smell. Penicillium commonly grows on water-damaged building materials such as ceiling and floor tiles, dried foodstuffs, vegetables, fresh fruits, spices, decaying vegetation, and soil. It is also present in house dust and indoor air as it often grows on air conditioning systems.

Some types of penicillium can cause issues such as allergic rhinitis and asthma. Immunocompromised people may develop serious and even fatal health issues if they come into contact with Penicillium. It is also associated with the development of occupational illnesses such as Cheese workers’ lung.

Alternaria Alternata

Unlike other types of mold, Alternaria alternata doesn’t usually grow on building materials. However, they will grow on damp textiles, canvas, paper, and cardboard as well as spoilt plant-based food. Alternaria alternata is also common indoors and it uses air conditioning systems to spread through houses. It is a significant risk factor for allergic rhinitis and asthma.

Alternaria usually doesn’t cause serious health problems in healthy adults but it can result in severe health outcomes in immunocompromised people.

Aspergillus Fumigatus

One of the most common types of mold, Aspergillus fumigatus, tends to grow in stored grain, compost piles, and decaying plant materials. Aspergillus also occurs on air conditioning systems and is common in most air-conditioned houses. It can grow on most substrates as long as they have adequate moisture and tends to thrive in cellars and basements. 

Furthermore, Aspergillus often grows in tandem with other types of mold, resulting in more negative health outcomes for both people with and without mold allergies. People with compromised immune systems may also develop Aspergillosis after they are exposed to Aspergillus.


Cladosporium is also abundant in both indoor and outdoor environments. It can be found growing on plant litter, old plants, and the soil. Indoors, it tends to grow in bathrooms, kitchens, and rooms with wallpaper that are likely to be more humid. Although most types of Cladosporium rarely cause severe human illness, exposure can still result in sinus, eye, and skin infections.

People with asthma may experience wheezing, sudden chest tightness, and trouble breathing after exposure to Cladosporium.

How to Prevent Mold Allergy

Various types of potentially dangerous airborne molds may be unavoidable but you can take steps to reduce your exposure. The following are some of the things you can do to avoid developing an allergy to mold or reduce mold exposure:

Keep Your Home as Dry as Possible

Eliminating excess moisture from your home will prevent mold from taking root in the first place. Start with basements and cellars where groundwater seepage and water pipe leaks are especially common and ensure there is no water leakage. Additionally, ensure the wallpaper installed in rooms like the bathroom and kitchen is vinyl-coated to ensure it doesn’t absorb moisture.

Avoid using moisture-absorbing materials such as rugs and carpets in basements and bathrooms as well. If your home was recently water-damaged due to flooding or large leaks, consider hiring a professional mold cleaning service to inspect the house for mold and prescribe further action.

Invest in a Dehumidifier

A dehumidifier will help you get rid of excess moisture in the air and keep indoor humidity levels under 50%. Just make sure you clean the condensation coils and collection buckets regularly to prevent mold growth on the humidifier.

Improve Your Home’s Ventilation

Poor ventilation coupled with high humidity is crucial to mold growth. Make sure you pay especially close attention to all your bathrooms as well as the kitchen as these rooms often have higher levels of moisture in the air. If possible, run a ventilation fan or open a window while you are showering to keep moisture levels low and inhibit mold growth.

Use Air Conditioners

Like dehumidifiers, air conditioners can also be instrumental in keeping indoor humidity levels low. This, in turn, discourages the growth and spread of mold in the house. Make sure your air conditioner is equipped with a high-efficiency particulate air (HEPA) filter attachment that can prevent outdoor mold from infiltrating your home and circulating indoors.

Store Old Newspapers and Books Properly

Leaving your old books and newspapers in damp conditions will promote the growth of mold and increase your risk of mold allergy. You can either store them in dry conditions by running a dehumidifier or fan in rooms with books or placing them on shelves with plenty of airflow.

Avoid placing bookshelves against the outside walls of the home and ensure books are dried in the sun as soon as they get wet.

Keep Your Home’s Exterior Dry and Debris Free

Invest in gutters that prevent groundwater drainage from seeping into your home and keep rainwater from pooling around the house. You should also clear any plant debris, such as fallen leaves and branches, from your yard. If you notice that any of your garbage cans have mold on the inside, throw them away and replace them with new ones.

Less mold outside your home means that there are fewer airborne mold spores to drift into your home and cause allergies.

Get Rid of Any Mold in Your Home

Whether or not you handle the mold removal yourself or call a professional will depend on the level of mold infestation. The United States Environmental Protection Agency (EPA) recommends that homeowners call professional mold removers when the infestation covers more than 10 square feet.

For minor mold infestations, you can use a solution of three parts water and one part bleach to soak the mold and surrounding wall for 10-15 minutes. Once this time elapses, use a scrubbing brush to remove all traces of the mold. Repeat the process as needed to completely remove the mold stains.

After that, spray a 50/50 mixture of hydrogen peroxide and white vinegar on the wall to kill the mold roots. You can also use vinegar and baking soda if you don’t have hydrogen peroxide. For mold growths on dry walls and those that cover more than 10 feet square, consider calling a professional to handle the cleanup on your behalf.

When to See a Doctor

People with compromised immune systems, asthma, or another lung condition, and those who are allergic to mold should seek medical attention as soon as they are exposed to mold. These groups of people are much more likely to experience serious symptoms after coming in contact with mold.

You should also see a doctor if you are unsure what’s causing your allergy symptoms as they can help identify what you’re allergic to and help you find relief.

How Are Mold Allergies Diagnosed?

Before you can receive a mold allergy diagnosis, your physician will run a physical examination and review your complete medical history. They will then order an allergy test if they suspect you have a mold allergy. However, you don’t have to visit a physician in person to identify what is triggering your allergy symptoms.

Now, there are plenty of at-home allergy tests that allow people to test if they are allergic to mold or other seasonal and environmental allergens. At Wyndly, our at-home allergy tests can be taken from the comfort of your home and only require a finger prick to collect a small blood sample. After sending your sample to our labs, our allergy doctors will interpret your results and create a personalized treatment plan for you.

How to Treat Mold Allergy

Various treatment approaches can reduce mold allergy symptoms. Here are the most over-the-counter (OTC) and prescription medications for mold allergy:

Nasal Corticosteroids

Nasal sprays tend to be one of the first lines of offense against mold allergies. They can help prevent and manage the inflammation caused by an allergic reaction to mold. Some of their side effects include nasal dryness and nosebleeds.


OTC antihistamines such as fexofenadine and loratadine can help temporarily relieve the symptoms of mold allergies. They help to reduce sneezing, itching, and nasal congestion by blocking an inflammatory chemical called histamine that is released during allergic reactions.

Oral Decongestants

Oral mold allergy medications can help reduce swelling and mucus levels in the airways to manage symptoms of asthma and mold allergies. Note that they may cause side effects such as insomnia, heart palpitations, anxiety, and high blood pressure in people with hypertension.

Nasal Decongestant Sprays

This OTC treatment works by reducing swollen blood vessels and tissues within the nose to alleviate congestion. Some side effects of nasal decongestant sprays include insomnia and headaches.

Sublingual immunotherapy

Treating mold allergy with sublingual immunotherapy involves taking allergy drops or tablets under the tongue every day to gradually reduce your sensitivity to mold allergens. Sublingual immunotherapy desensitizes the immune system over time and prevents it from reacting to mold allergens, resulting in long-term relief. Unlike allergy shots, sublingual immunotherapy can be safely taken at home.

Take Our Allergy Assessment

If you are seeking long-term relief from mold allergy symptoms, choose Wyndly. Our allergy doctors will determine if you are eligible for sublingual immunotherapy and create a personalized treatment plan that will help you gain long-term relief from your allergy symptoms.

Take our quick online assessment to begin your journey to an allergy-free future.

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