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The most common allergens in the home are house dust mites, pet allergens and moulds. Mould is a generic term used for hundreds of different species of fungi. Cladosporium is one of these fungi that grows in damp places, such as bathrooms, and can trigger allergic reactions and respiratory problems in susceptible people.

What is it?

Cladosporium is one of the most common groups of fungi found in homes. It can trigger a range of allergies in those who are sensitive to it. Cladosporium can be the cause of rare allergic lung diseases, such as ‘hot tub lung’, when people are repeatedly exposed to it in high concentrations. It appears as a dark-green, brown or black layer on surfaces within the home.

How does is it spread?

Cladosporium is often found outdoors, particularly on food waste and decaying plants. Indoors, it can grow on damp surfaces, particularly on wood and fabrics. Cladosporium doesn’t live on skin, unlike some other fungi, but when it releases spores that travel through the air, it also releases musty-smelling chemicals that can trigger allergic reactions.

Who is at risk?

People who suffer from respiratory allergies, such as hayfever and asthma. Some people who become allergic to Cladosporium can suffer severe allergic reactions in their lungs.

What are the symptoms?

  • Exposure to Cladosporium and the allergens it releases can trigger asthma attacks (wheezing and difficulty breathing) and symptoms of hayfever, such as itchy, watering eyes, sneezing and a blocked nose.
  • Symptoms of acute allergic lung disease include raised temperature, chills, headache, cough and chest tightness, which will resolve in around 12 hours. Some people develop fatigue and experience weight loss.
  • Symptoms in your home include dark, visible growths and stains on surfaces.

Prevent the spread

  • Disinfect surfaces where you can see the dark, visible layer of fungus with a bleach-based cleaning product, such as Domestos Bleach Spray or Domestos Extended Germ-Kill.
  • Try to reduce the number of damp areas in your home – dry off the bathroom floor after you've showered and let your shower dry out properly. Dry off kitchen sinks and draining boards after use.
  • Don't store food waste, on which fungi can grow, indoors for long periods of time.
  • Wrap up food waste or other rotting organic waste before disposal, and avoid disturbing it in a way that may release spores into the air.
  • Keep waste bins clean.
  • People with respiratory illnesses such as asthma, or those with reduced immunity due to illness or old age, should try to avoid places with visible mould, or coming into contact with rotting waste.