17 Signs of Mould Illness You Shouldn’t Ignore

Indoor mould exposure can trigger a wide range of health issues—from brain fog and fatigue to respiratory irritation and mood changes. Sometimes, the real threat is invisible.

Mould can grow in hidden corners of your home—under carpets, inside HVAC systems, or behind damp walls—and slowly impact your health without you knowing. In this article, we break down what mould illness really is, the key symptoms to look out for, and what you can do to protect your household.

Understanding Mould Illness and How It Impacts Your Health

Mould illness also called chronic inflammatory response syndrome (CIRS)—is a serious condition caused by long-term mould exposure, particularly in damp or water-damaged buildings. Unlike a typical mould allergy, which causes sneezing and itchy eyes, mould illness affects your brain, lungs, gut, skin, and immune system.

People with asthma, chronic illness, or weakened immunity may be especially vulnerable. Their bodies often struggle to detoxify the mycotoxins released by mould, allowing inflammation to build over time.

Mould spores enter the body through breathing, skin contact, or ingestion. Once inside, they can affect neurological function, hormones, digestion, and energy production—making it hard to pinpoint a clear cause.

Read Also: The Hidden Health Risks of Mould: What You Need to Know

Here are the 17 Signs of Mould Illness to Watch For

Cognitive and Neurological Symptoms

1. Brain Fog

Mental "cloudiness," forgetfulness, and difficulty focusing.

2. Memory Issues

Short-term memory lapses and trouble recalling basic information.

3. Headaches or Migraines

Recurring headaches that worsen in damp or musty environments.

4. Mood Swings, Anxiety, or Depression

Unexplained emotional changes, irritability, or depressive thoughts.

Respiratory and Allergy Symptoms

5. Chronic Coughing

A persistent dry or mucus-producing cough that resists treatment.

6. Wheezing or Shortness of Breath

Breathing difficulties, especially indoors or near mould-prone areas.

7. Nasal Congestion or Sinus Pressure

Constant stuffiness, sinus infections, or postnasal drip.

8. Itchy Throat, Eyes, or Ears

Allergy-like irritation that flares indoors and resolves outdoors.

Skin and Sensory Reactions

9. Rashes or Skin Irritation

Hives, eczema, or unexplained skin inflammation.

10. Sensitivity to Light or Noise

Heightened sensitivity that doesn't have a neurological cause.

11. Red, Itchy, or Watery Eyes

Eye symptoms that mimic hay fever but persist indoors.

Systemic and Digestive Symptoms

12. Fatigue or Chronic Exhaustion

Extreme tiredness that sleep doesn't fix—a hallmark of mould toxicity.

13. Muscle Aches or Joint Pain

Ongoing pain not linked to exercise or injury.

14. Nausea, Bloating, or Stomach Cramps

Digestive issues that mirror IBS or food intolerances.

15. Night Sweats or Low-Grade Fevers

Subtle signs of systemic inflammation and toxic buildup.

16. Flare-Ups That Follow You Home

Symptoms improve when you're away, worsen when you're back.

17. No Clear Diagnosis Despite Testing

Chronic symptoms with no explanation may point to hidden mould.

Mould Illness vs. Mould Allergy: What Makes Them Different?

Mould allergy causes symptoms like sneezing, congestion, and itchy eyes. Mould illness (also called mould toxicity), on the other hand, is a multi-system inflammatory condition that can resemble more severe disorders:

• Chronic Fatigue Syndrome

• Fibromyalgia

• Depression or anxiety

• IBS or food sensitivities

Mould allergy often improves with antihistamines. Mould illness does not.

Where Mould Hides: Environmental Clues You Shouldn’t Miss

Even if mould isn’t visible, it can thrive in dark, damp places, including:

• HVAC systems

• Behind wallpaper or drywall

• Under carpets or floorboards

• Inside cupboards and around sinks

• Attics, crawlspaces, and basements

  
  

Prevention Tips:

• Use dehumidifiers to keep humidity under 50%

• Fix leaks promptly

• Install proper ventilation in kitchens and bathrooms

• Schedule mould inspections, especially after water damage

Detoxing Your Home and Supporting Your Recovery

True healing starts by removing the source of exposure. No amount of supplements will help if you’re still living with mould.

What to Do:

• Hire a Mould Professional – DIY cleanup often misses hidden growth.

• Fix Moisture Problems First – Mould can’t grow without moisture.

• Use HEPA Filters – Clean indoor air and capture spores.

• Avoid Bleach – It doesn’t kill mould roots and may worsen air quality.

Remember, a safe living environment is essential to healing. Treat your space as part of your recovery plan.

Read Also: Identifying Common Household Moulds in Victoria

Final Thoughts: Listen to Your Body

If doctors can’t explain your symptoms and you feel better away from home, mould illness could be the reason.

At Kepal Building Services, we help uncover hidden mould, repair damage, and restore healthy indoor environments. Book your mould inspection today and take the first step toward a healthier home.