Drying Clothes Indoors: How Mould Can Affect Your Health

Putting washing out to dry in the garden has been an uncommon sight over the past few months, as winter storms have brought freezing conditions and wind gusts of up to 100 mph. Yet, does it really make a difference how we dry clothes indoors?

Drying damp clothes on airers in rooms with inadequate ventilation may raise the amount of mould in the home. Mould is linked to poor health and can, in certain circumstances, lead to death.

When mould develops indoors, it may appear as black or green patches on walls and commonly produces an unpleasant, musty odour. It should not be disregarded: prolonged exposure to mould can carry serious consequences for health.

Mould is an umbrella term for a range of fungi that release minute particles known as spores. Fungi generate spores when the conditions support their growth, including lower temperatures and high humidity.

For this reason, mould is particularly likely to grow on bathroom ceilings or damp walls, where fungal spores have more moisture in which to settle and develop.

Indoor clothes drying and mould growth

There are numerous species of mould, but penicillium and aspergillus are the types most often responsible for problems in damp homes. It is estimated that we inhale low numbers of spores from these fungi every day.

Fortunately, the immune system is highly effective at recognising and destroying fungal spores. This helps keep fungal lung infections in people relatively uncommon, despite our continual exposure. Immune cells known as macrophages are located in the lungs' air spaces, called alveoli. They consume inhaled material that may be harmful, including fungal spores.

Risks for compromised immune systems

However, some people have immune systems that cannot clear fungal spores. In these circumstances, fungi may cause dangerous infections or significantly worsen existing conditions, such as asthma.

Those with damaged or compromised immune systems face a greater risk of becoming seriously ill because of fungal infections. Moulds such as aspergillus can infect people with reduced immune function or lung damage caused by conditions including asthma, cystic fibrosis and chronic obstructive pulmonary disease (COPD) linked with heavy smoking.

For people with asthma, the immune system responds excessively to triggers, including fungal spores, resulting in inflammation in the lungs. By narrowing the airways, this inflammation makes breathing more difficult.

Asthma symptoms and allergic reactions result from the same form of immune response, which fungal spores can also provoke. Consequently, spores can be an especially potent trigger for certain people.

In the most severe cases, spores can do more than trigger inflammation: they may enter and obstruct the airways, causing bleeding in the lung. This occurs when spores germinate and produce long, spiderweb-like structures called mycelium. These form sticky masses that obstruct airways and harm delicate lung tissue.

Growing resistance

Azoles are antifungal medicines used to treat aspergillus infections. They work by stopping fungal cells from developing correctly. Although azoles are highly effective, aspergillus is showing rising levels of azole resistance, which is a major concern.

Only a limited selection of antifungal medicines is available for treating mould infections. Once resistance emerges, the treatment options open to a patient can be drastically reduced.

Resistance to medicines such as azoles may arise in patients who use them over long periods. However, recent research suggests it more commonly develops in the environment, where most fungi live. As a result, an aspergillus infection could already be resistant to antifungal treatment before a patient is even diagnosed.

Drug resistance in environmental fungi has been associated with the agricultural use of azoles and other antifungal medicines. Fungal infections pose a major threat to crops, and plants require protection from them just as people do. Unfortunately, the drugs used in clinical settings are the same types as those used in agriculture.

Climate change could also be contributing to drug resistance among environmental fungi. Recent findings showed that exposure to high temperatures can help moulds become resistant to commonly prescribed antifungal medicines.

There have also been reports of patients falling ill due to mould species previously not considered capable of causing disease in humans, partly because they were unable to grow at human body temperature.

It is therefore possible that additional mould species may acquire the capacity to cause infections while also becoming drug resistant. Research programmes and healthcare initiatives that track these developments are essential if we are to prepare for possible rises in mould infections.

Keeping homes free from mould

For people with healthy immune systems, normal exposure to fungal spores is unlikely to create health problems. However, exposure to extremely high quantities of fungal spores can be fatal, even in those without underlying health conditions.

In 2020, toddler Awaab Ishak died directly as a result of substantial exposure to fungal spores caused by excessive damp and mould in his home.

His death resulted in a change to UK law, Awaab's Law. It requires landlords to act promptly when damp is identified in properties they manage, so tenants are not exposed to excessive fungal spore levels that can harm their physical and mental health.

It is important, therefore, to prevent mould from developing in the home. Ensuring effective ventilation is the best approach, alongside measures to limit damp, such as using a dehumidifier or buying a heated clothes airer for drying clothes indoors during winter.

Rebecca A. Drummond, Associate Professor, Immunology and Immunotherapy, University of Birmingham

This article is republished from The Conversation under a Creative Commons licence. Read the original article.