Mould Infection: What It Is, Types, Symptoms, Risk And More

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Mould Infection: What It Is, Types, Symptoms, Risk And More

Exposure to mould, especially mould grown indoors, can trigger allergies and infections in people.

Mould infection: What it is, types, symptoms, risk and more

Image Source: Dinodia

Moulds, refers to a type of organism belonging to the fungi family and can be found in abundance both indoors and outdoors, including on plants, food, and dry leaves. Mould spores, being minuscule and lightweight, have the ability to travel effortlessly through the air and have the ability to thrive both indoors and outdoors. 

In outdoor environments, moulds play a crucial role in the ecosystem by aiding in the decomposition of plant and animal materials. However, when mould grows indoors, it can occasionally pose problems. Allergic symptoms such as watery eyes, runny nose, sneezing, itching, coughing, wheezing, difficulty breathing, headache, and fatigue may arise from being exposed to a significant amount of mould spores. Continuous exposure to mould can heighten an individual's sensitivity, leading to more severe allergic reactions. Indoors, mould exacerbates air quality issues, making these problems even more pronounced. In specific circumstances, certain moulds like Stachybotrys and Aspergillus can generate toxins known as mycotoxins. Exposure to mycotoxins can result in more severe illnesses.

Moulds can find their way into your home through various means. Open doorways, windows, vents, and heating and air conditioning systems can serve as entry points for mould. Additionally, mould spores present in the outdoor air can attach themselves to clothing, shoes, and pets, and inadvertently be brought indoors.

Types of Indoor Moulds

Here are the most frequently encountered types of indoor moulds:

  1. Cladosporium - Cladosporium can appear in shades of brown, green, or black .It thrives in both warm and cool surroundings and is frequently discovered on wood, carpets, fabrics, as well as in heating and cooling ducts.
  2. Penicillium - This mould has a fuzzy texture and can display colours such as blue, green, or yellow. It is often discovered beneath carpets, in basements, and in insulation, particularly in areas affected by water damage.
  3. Aspergillus - Aspergillus moulds can appear green, white, or grey and have dark spots and a powdery appearance. They do not require substantial ventilation to thrive and are commonly found in fabrics, walls, attics, basements, and even on dry food items.
  4. Household mould - Mould growth in a house can manifest in various colours such as black, white, or spotted, exhibiting textures ranging from powdery to cottony or velvety.

To determine if a suspicious spot indicates a mould issue rather than an old stain or dirt, consider the following indicators:

  1. Musty or earthy odour - Mould often emits a distinct smell that is damp and earthy in nature.
  2. Moisture source - If the spot is located in an area with a nearby source of moisture but lacks ample light, it is more likely to be mould.
  3. Damage to materials - Look for signs of warping, cracking, or peeling on the surface where the spot is growing. Mould tends to cause deterioration in the materials it colonises.
  4. Bleach test - Place a drop of bleach on the spot and observe if its colour lightens within a minute or two. Mould is typically affected by bleach, causing a noticeable change in colour, whereas dirt and old stains remain unaffected.

Remember that mould growth can proliferate if left unchecked, while dirt and stains do not exhibit such growth patterns.

Symptom of Mould infection

While the presence of mould in your residence may not automatically result in illness, it does possess the capacity to trigger specific health problems.

Direct contact with or inhalation of mould spores can lead to symptoms resembling allergies, including:

  1. Excessive nasal discharge and congestion
  2. Irritated eyes
  3. Frequent sneezing
  4. Persistent coughing
  5. Sore throat
  6. Skin rash
  7. Headaches
  8. Irritation of the lungs
  9. Wheezing


Mould spores are omnipresent, and they are inhaled by everyone. However, some individuals experience mould allergies due to their immune systems reacting excessively to specific types of mould that are considered allergens by the body. Consequently, this immune response can lead to symptoms like sneezing and nasal congestion. 

It's important to note that not all moulds trigger allergic reactions. The primary culprits responsible for mould-induced allergy symptoms include:

  1. Alternaria
  2. Aspergillus
  3. Cladosporium
  4. Penicillium


If you suspect that you are experiencing symptoms of mould exposure, it is advisable to inform a healthcare professional. Differentiating between mould, other conditions, or allergies can be challenging without proper evaluation. Your doctor may conduct skin or blood tests to accurately diagnose a mould allergy.

Treatment options and preventive measures for mould allergies may include

  1. Use of nasal corticosteroid sprays and antihistamines to alleviate symptoms
  2. In cases of severe and persistent symptoms throughout the year, allergy shots may be recommended
  3. Maintaining humidity levels below 50 percent using a dehumidifier
  4. Ensuring adequate ventilation in humid areas
  5. Promptly addressing any leaks through timely repairs


While mould in your home may not always result in health issues, it is crucial to remove it regardless. Mould has the potential to cause damage to your home and can lead to irritation in various areas such as the eyes, nose, throat, and lungs. Individuals with a mould allergy or chronic lung condition like asthma are at a higher risk of experiencing more severe symptoms and complications. To minimise indoor mould growth, incorporating a few home maintenance tasks can be helpful. However, if you come across significant mould infestation or have respiratory problems, it is advisable to seek assistance from a professional contractor who can safely remove the mould and perform the necessary repairs.

Disclaimer: The above content is for informational purposes only and should not be used as a substitute for the advice of a qualified physician or doctor. The Company does not vouch for or endorse any of the above content, and disclaims any and all warranties, express or implied, relating to the same.