Mould Allergy: Symptoms, Triggers & Home Prevention Tips

What is a Mould Allergy?

A mould allergy occurs when your immune system becomes overly sensitive to mould spores present in the air. Moulds are microscopic fungi that thrive in warm, damp, and humid environments — both indoors and outdoors.

When you breathe in these airborne spores, your body mistakes them for harmful pathogens and mounts an allergic response. This reaction leads to symptoms such as sneezing, nasal congestion, a runny nose, coughing, itchy eyes, and even skin irritation.

Unlike seasonal allergies that peak at specific times of the year, mould allergy symptoms can occur year-round, especially if you live in regions with high humidity or poor ventilation. Understanding your body’s response to mould and identifying potential sources in your surroundings is the first step toward effective management.

How Common is Mould Allergy?

Mould allergies are more common than many people realise. Millions of individuals worldwide experience allergic symptoms triggered by moulds, such as Aspergillus, Cladosporium, Penicillium, and Alternaria.

According to a review published in the International Journal of Academic Medicine and Pharmacy, in tropical and subtropical countries like India, mould allergies can persist, especially during the monsoon season when humidity is high. People living in coastal regions or older homes with damp walls and poor ventilation are particularly at risk. Children, the elderly, and those with respiratory conditions, such as asthma or chronic sinusitis, are also at a higher risk.

How Does a Mould Allergy Develop (Mechanism)?

When mould spores enter the body, the immune system releases IgE antibodies to fight them. Upon repeated exposure, these allergens trigger the release of histamine, leading to symptoms such as sneezing, congestion, watery eyes, and skin irritation. Continued exposure heightens sensitivity, resulting in increasingly severe allergic reactions over time.

Common Types of Moulds That Cause Allergy

Several types of moulds are known to trigger allergic reactions.

The most common include:

• Alternaria: Commonly found outdoors on soil, plants, and decaying vegetation; peaks during late summer and autumn.
• Aspergillus: Grows indoors on dust, damp walls, and air-conditioning vents.
• Cladosporium: Appears on damp wood, carpets, and fabric.
• Penicillium: Grows on spoiled food, wallpaper, and other water-damaged materials.
• Stachybotrys (Black Mould): Develops on water-damaged walls and ceilings; prolonged exposure can worsen respiratory symptoms.

Symptoms of Mould Allergy

Mould allergy symptoms vary from mild to severe depending on your exposure and sensitivity.

Common mould allergy symptoms include:

1. Frequent sneezing and nasal congestion
2. Runny or stuffy nose
3. Itchy, red, or watery eyes
4. Postnasal drip or sore throat
5. Coughing or wheezing
6. Fatigue and headache due to sinus pressure
7. Skin irritation, rash, or hives
8. Breathing difficulties (especially in people with asthma)

When Mould Allergy Becomes Severe / Complications

While most mould allergies cause mild discomfort, severe or prolonged exposure can lead to chronic respiratory issues. You should be cautious if symptoms persist despite medication or appear alongside the following complications:

• Asthma exacerbation: Mould spores can trigger asthma attacks, causing chest tightness, coughing, and wheezing.
• Allergic fungal sinusitis: Persistent nasal blockage or sinus pain caused by mould growth in the sinuses.
• Hypersensitivity pneumonitis: An immune system disorder causing lung inflammation from repeated exposure.
• Fungal infections: Rarely, individuals with weakened immune systems (such as those undergoing chemotherapy or organ transplants) may develop infections in the lungs or sinuses due to Aspergillus or similar moulds.

Triggers & Risk Factors for Mould Allergy

Certain factors can increase your likelihood of developing a mould allergy:

• Family history of allergies
• Asthma or other respiratory diseases
• Living in a damp or humid environment
• Occupational exposure (e.g., farming, construction)

a. Indoor Triggers (Household Sources, Damp Areas)

• Leaking roofs, pipes, or basement seepage
• Bathrooms and kitchens lacking proper ventilation
• Carpets, curtains, and upholstery that retain moisture
• Air conditioners, humidifiers, and refrigerators with dirty or mouldy filters
• Houseplants or flowerpots with damp soil
• Stored items such as clothes, papers, or cardboard boxes kept in humid storage spaces

b. Outdoor Triggers (Spore Seasons, Weather, Yard Moulds)

• Piles of wet leaves, compost heaps, or decaying wood
• Agricultural fields and gardens after rainfall
• Humid weather conditions and monsoon seasons
• Airborne spores are more prevalent during late summer and early autumn

Examinations and Tests to Diagnose Mould Allergy

Diagnosing a mould allergy typically involves a combination of clinical evaluation and laboratory tests.

Your doctor may recommend:

• Skin Prick Test: Small drops of mould allergens are placed on your skin to check for allergic reactions.
• Specific IgE Blood Test: Measures the immune system’s response to mould exposure.
• Spirometry or Lung Function Test: Determines how well your lungs work, especially if asthma is suspected.
• Allergy Tests: Tests such as the Allergen, Individual–Microorganism Aspergillus fumigatus and Penicillium chrysogenum panels, or a general Phadiatop IgE screening test, can help identify mould sensitivities or Allergy Phadiatop Test - Screening IgE With (Adult & >5y) help determine the source/presence of the allergen in your body based on its IgE response.

Treatment & Management Options

Managing mould allergy involves reducing exposure and treating symptoms.

a. Medications (Antihistamines, Nasal Steroids, Decongestants)

• Antihistamines: Help reduce sneezing, itching, and nasal discharge.
• Nasal corticosteroids: Relieve nasal inflammation and congestion.
• Decongestants: Provide temporary relief from nasal stuffiness by constricting swollen blood vessels.
• Leukotriene modifiers: Help control airway inflammation in chronic cases.

b. Allergy Shots / Immunotherapy

If symptoms persist despite medication, your allergist may recommend immunotherapy as a treatment option. This involves regular injections of small doses of mould allergens to gradually train your immune system to tolerate them better. Immunotherapy provides long-term relief and reduces dependence on medication.

c. Supportive Remedies (Nasal Rinses, Air Filters, etc.)

• Rinse your nasal passages with saline water to remove allergens.
• Install HEPA air filters to capture airborne spores.
• Maintain indoor humidity levels below 50% by using a dehumidifier.
• Clean air-conditioning ducts, filters, and vents regularly.
• Use mild, non-toxic cleaning agents (such as vinegar or baking soda solutions) to remove visible mould.

Home Prevention Tips & Strategies

To reduce mould exposure in your home:

1. Fix plumbing or roof leaks immediately to prevent water accumulation.
2. Dry wet areas within 24–48 hours to avoid mould growth.
3. Use exhaust fans in bathrooms and kitchens to control humidity.
4. Avoid carpeting in damp areas like basements or bathrooms.
5. Clean bathrooms weekly with antifungal cleaners.
6. Keep indoor humidity low, ideally between 30% and 50%.
7. Avoid drying clothes indoors where air circulation is poor.
8. Inspect air conditioners, dehumidifiers, and roofs regularly for moisture or leaks.
9. Dispose of old books, fabrics, or cardboard boxes that have absorbed moisture, as they are common mould reservoirs.

Monitoring & When to Call a Professional

You should consult a doctor if you:

• Experience symptoms for more than two weeks despite home care
• Have recurrent sinus infections or worsening asthma symptoms
• Notice skin rashes or fatigue linked to damp environments.
• Struggle with shortness of breath, chest pain, or coughing fits.

Outlook & Living Well with Mould Allergy

Living with a mould allergy doesn’t have to limit your lifestyle. With timely diagnosis, proper medication, and preventive measures, you can effectively manage symptoms. Regular home maintenance, humidity control, and routine health monitoring are key to preventing flare-ups.

If your symptoms persist or worsen, it’s wise to undergo an allergy test and follow a personalised care plan prescribed by your doctor.

Conclusion

A mould allergy is your body’s way of signalling sensitivity to environmental triggers, but it can be effectively managed with awareness and timely intervention. By maintaining dry, well-ventilated spaces and seeking medical guidance when needed, you can control symptoms and protect your respiratory health.

For accurate mould allergy testing and professional insights, trust Metropolis Healthcare. With 4,000+ diagnostic tests, expert pathologists, and over 10,000 touchpoints for home sample collection services, Metropolis ensures you get precise results and peace of mind — right from the comfort of your home.

FAQs

What is the difference between mould allergy and mould irritation?

Mould allergy triggers your immune system to overreact, causing symptoms like sneezing or congestion. Mould irritation, however, results from direct exposure to spores and does not involve an immune response.

Can mould allergy develop later in life?

Yes. Even if you’ve never had allergies before, prolonged exposure to damp environments can cause mould sensitivity over time.

Does mould allergy worsen asthma?

Yes, mould spores are common asthma triggers and can increase the frequency or severity of attacks.

Can a mould allergy go away on its own?

While mild symptoms may fade after removing the source of exposure, allergies rarely go away completely without treatment or preventive care.

Is black mould more dangerous for allergy sufferers?

Yes. Stachybotrys chartarum (black mould) produces irritants that can cause stronger allergic or respiratory reactions, especially in people with asthma.

How soon do mould allergy symptoms appear after exposure?

Symptoms typically appear within minutes to hours after exposure and may last several days if the environment remains damp.

Can a mould allergy cause a skin rash or hives?

Yes, prolonged contact with mould spores can lead to rashes, hives, or itching on sensitive skin.

References

1. https://www.aaaai.org/conditions-treatments/library/allergy-library/mold-allergy
2. https://allergyasthmanetwork.org/allergies/mold-allergy/
3. https://www.beckerent.com/education/mold-allergies
4. https://acaai.org/allergies/allergic-conditions/mold-allergy/
5. https://www.mayoclinic.org/diseases-conditions/mold-allergy/diagnosis-treatment/drc-20351526
6. https://my.clevelandclinic.org/health/diseases/8622-mold-allergies
7. https://www.metropolisindia.com/blog/preventive-healthcare/allergies
8. https://www.aaaai.org/Aaaai/media/Media-Library-PDFs/Allergist%20Resources/Statements%20and%20Practice%20Parameters/Fungi-and-allergic-lower-resp-tract-dis-2012.pdf
9. https://my.clevelandclinic.org/health/articles/11641-mol
10. https://academicmed.org/Uploads/Volume5Issue5/279.%20[1717.%20JAMP_Mohamed%20Ali_QR]%201408-1413.pdf