Mould allergy – Immune system and chronic fungal infections
Mould (Fungal) Allergy – Testing and Immune Response
Mould allergy is caused by an IgE-mediated immune response to airborne fungal spores. These spores are inhaled into the nose, sinuses, and lungs and can trigger allergic symptoms in sensitised individuals.
Moulds grow in humid environments, such as bathrooms, kitchens, behind furniture, under window seals, or in properties affected by leaks or flooding. While mould exposure is common, only some people develop allergy.
Symptoms Suggesting Mould Allergy
Mould allergy may present as:
– Persistent or seasonal nasal congestion
– Sneezing and runny nose
– Itchy, red, watery eyes
– Cough, wheeze, or chest tightness
– Asthma flare-ups in damp environments
Mould Allergy – Why It Matters
Moulds are fungi that grow in humid and poorly ventilated environments. Black or green spots in showers, behind wardrobes, under window seals, or after leaks are common signs of mould growth.
Moulds release microscopic spores into the air. When inhaled, these spores can reach the nose, sinuses, and lungs. In people who have developed allergic sensitisation, this exposure can trigger symptoms ranging from mild hay-fever-like reactions to severe asthma attacks.
Importantly, not all mould exposure is harmful. Problems arise when:
– A person is allergic (IgE-mediated sensitisation)
– Exposure is heavy or prolonged
– There is underlying lung disease or immune weakness
Mould is everywhere even in Space in the International Space Station
How Mould Triggers the Immune System
Moulds grow as branching filaments called mycelium and reproduce by releasing airborne spores. These spores contain proteins that may act as allergens.
In sensitised individuals:
– The immune system produces specific IgE antibodies to mould allergens
– Re-exposure leads to mast-cell activation
– Histamine and inflammatory mediators are released
This immune response causes:
– Sneezing and nasal blockage
– Runny or itchy nose
– Red, itchy, watery eyes
– Cough, wheeze, or shortness of breath
– Asthma exacerbations
Common allergenic moulds include Alternaria, Cladosporium, Aspergillus, and Penicillium.
Mould Allergy vs Toxic Effects vs Infection – Key Differences
1. Mould allergy (immune-mediated)
– Occurs only in sensitised individuals
– Symptoms improve with allergen avoidance or antihistamines
– Confirmed by skin prick testing or specific IgE blood tests
2. Non-allergic mould-related symptoms
Some moulds produce mycotoxins. In damp buildings, people may report:
– Headaches
– Fatigue
– Brain fog
– Irritated eyes or throat
A typical feature is that symptoms resolve completely when away from the property (for example, on holiday or staying with friends) and recur on return. Often, multiple household members are affected.
3. Chronic fungal infections
These occur mainly in:
– People with weakened immune systems
– Chronic skin or mucosal disease
– Certain lung conditions
Examples include chronic fungal sinusitis or skin fungal infections, which require specialist assessment and targeted treatment.
Seasonal and Indoor Exposure in the UK
Outdoor mould spores
In the UK, outdoor mould spores:
– Appear from late winter
– Peak from August to November
– Are highest in warm, damp conditions
Indoor mould exposure
Indoor moulds can be present all year round. Levels often rise when outdoor spore counts are high, as spores enter through windows and ventilation.
Indoor growth is encouraged by:
– High humidity
– Poor ventilation
– Water damage or leaks
– Organic materials such as wet wood, wallpaper, and carpets
Reducing Exposure – Practical Prevention
The most effective way to reduce mould exposure is humidity control:
– Keep indoor humidity below 50–60%
– Ventilate kitchens and bathrooms
– Repair leaks promptly
– Avoid drying clothes indoors without ventilation
If mould is visible:
– Small areas may respond to appropriate antifungal cleaning
– Extensive contamination may require professional remediation
When to Consider Allergy or Immunology Testing
Testing is useful when symptoms suggest allergy rather than infection or irritation.
At London Allergy and Immunology Centre, specialist consultations are available for:
– Suspected mould allergy
– Asthma worsened by damp environments
– Chronic nasal or sinus symptoms
– Recurrent skin or mucosal fungal disease
Investigations may include:
– Specific IgE blood tests
– Skin prick testing
– Targeted immunological assessment
Chronic Lung Disease and Mould Exposure
In rare cases, prolonged exposure to domestic moulds has been linked to interstitial lung disease and hypersensitivity pneumonitis. These conditions present with:
– Progressive breathlessness
– Chronic cough
– Abnormal lung imaging
Early recognition and environmental control are essential.
Mould Exposure in Early Life
Research shows that damp and mouldy home environments in early childhood are associated with an increased risk of:
– Asthma
– Wheezing disorders
– Allergic disease later in life
This highlights the importance of addressing housing conditions early, particularly for families with young children.
Key Take-Home Messages
– Mould is common, but only causes symptoms in certain situations
– Allergy, toxicity, and infection are distinct conditions
– Allergy testing helps identify clinically relevant sensitisation
– Humidity control and remediation reduce exposure
– Specialist assessment ensures accurate diagnosis and treatment
Schimmelpilze: Achtung Allergiegefahr!
Schimmelpilze gedeihen dort, wo es feucht ist. Schwarze Flecken in der Dusche, hinter dem Schlafzimmerschrank oder unter Gummidichtungen stellen nahezu untrügliche Anzeichen dar. Das Hinterhältige an
den Schimmelpilzen sind die Sporen. Sie verbreiten sich über die Luft und gelangen so in die Atemwege. Einige Menschen reagieren darauf mit einer Allergie.
Mould: Attention – Risk of Allergy!
Moulds thrive wherever it is damp. Black spots in the shower, behind bedroom wardrobes, or under rubber seals are almost unmistakable signs of mould growth.
What makes mould particularly problematic is its spores. These spread through the air and can easily enter the airways when inhaled. Some people react to these spores with an allergic response.
Symptoms often worsen indoors or improve when staying away from the affected property.
Common Allergenic Moulds Tested
Clinical testing focuses on moulds known to cause respiratory allergy, including:
– Alternaria alternata
– Cladosporium herbarum
– Aspergillus fumigatus
– Penicillium species
Outdoor mould spores in the UK peak from late summer to autumn (August–November), while indoor mould exposure occurs year-round.
Mould Allergy vs Fungal Infection vs Toxic Exposure
It is important to distinguish between three different conditions:
Mould allergy
– Immune-mediated (IgE)
– Occurs only in sensitised individuals
– Diagnosed by allergy testing
Non-allergic mould exposure
– May cause headaches, fatigue, eye or throat irritation
– Often affects multiple household members
– Symptoms improve away from the property
Chronic fungal infection
– Affects skin, nails, sinuses, or lungs
– More common in immunocompromised individuals
– Requires specialist medical treatment
Allergy tests are not designed to diagnose infection, but help confirm allergic sensitisation.
How Mould Allergy Is Diagnosed
At London Allergy and Immunology Centre, mould allergy testing may include:
Skin prick testing
– Immediate results
– Identifies IgE sensitisation to specific moulds
Specific IgE blood tests
– Useful when skin testing is unsuitable
– Helps assess severity and relevance
Results are always interpreted alongside:
– Symptom history
– Home and work environment
– Asthma or sinus disease
Why Accurate Testing Matters
Mould is present everywhere – even in extreme environments such as the International Space Station – but unnecessary avoidance or anxiety can be avoided with correct diagnosis.
Accurate testing helps:
– Confirm or exclude mould allergy
– Identify asthma triggers
– Guide environmental control measures
– Avoid unnecessary antifungal treatments
Environmental Control and Prevention
Key measures include:
– Reducing indoor humidity
– Improving ventilation
– Repairing leaks promptly
– Professional mould remediation when needed
Small surface mould can often be managed safely, while extensive contamination may require specialist cleaning.
When to See a Specialist
You should consider specialist assessment if you have:
– Persistent nasal or chest symptoms
– Asthma worsened by damp environments
– Recurrent sinus or fungal skin disease
– Symptoms affecting multiple family members
SEO-friendly FAQ (recommended addition)
Can mould allergy cause asthma?
Yes. Mould allergy is a recognised trigger for asthma symptoms and exacerbations.
Is black mould always dangerous?
Not always. Risk depends on the mould species, level of exposure, and individual sensitisation.
Do I need home mould testing or allergy testing?
They answer different questions. Allergy testing assesses your immune response; environmental testing assesses the property.