Athlete’s foot can become ‘untreatable’ even with the strongest over-the-counter creams, due to the rise of drug-resistant strains of the bug that causes the common skin infection.
One of the most used medications, Lamisil Once, was able to fight off the condition with a single dose when it launched in the 1990s – but increasing numbers of patients are finding the remedy useless, say experts.
And concerns are not just about athlete’s foot, which causes the skin between the toes to become painful and cracked. One clinician said antifungal treatments are now ineffective in about a third of all skin infections he treats.
Athlete’s foot is caused by a type of fungi called dermatophytes which also causes ringworm – characterised by painful, scaly, red rashes that can appear anywhere on the body. These infections affect millions of people in the UK every year.
Much has been written about bacterial infections that are resistant to antibiotics – making once treatable conditions like urinary tract infections potentially lethal.
Athlete’s foot can become ‘untreatable’ even with the strongest over-the-counter creams, due to the rise of drug-resistant strains of the bug that causes the common skin infection
But experts are seeing a similar pattern with everyday fungal infections. And there are fears the NHS could soon run out of effective treatments.
‘We’re seeing more and more drug-resistant fungal skin infections and, frankly, the issue has not had nearly enough attention,’ says Dr Neil Stone, a consultant in infectious diseases and microbiology at University College London Hospitals NHS Foundation Trust.
‘These sorts of problems are very prevalent and if the treatments we rely on stop working, that will be a massive health problem with huge ramifications.’
Some 15 per cent of people have suffered a fungal skin infection in the past year. The scaly, red rashes are far more common in elderly people, affecting around half of people aged over 70.
The drug recommended by the NHS to treat athlete’s foot is terbinafine, the active ingredient found in Lamisil Once and other over-the-counter treatments. But this is one of the medications becoming increasingly ineffective, experts warn
There are several strains of dermatophyte, which are usually passed on via skin-to-skin contact. The fungal spores can live on the skin and under fingernails for some time without triggering a rash and they thrive in warm, damp places such as wet towels and the floors of changing rooms.
This is why athlete’s foot – a form of dermatophyte which gets between the toes – is often picked up in communal showers.
The fungi can also infect the scalp, causing a form of dandruff.
Drying the area affected – for example, by using talcum powder – can help reduce the severity of the rash but cannot cure it. Specific antifungal treatments are the only effective route to destroying dermatophytes.
The drug recommended by the NHS is terbinafine, the active ingredient found in Lamisil Once and other over-the-counter treatments. But this is one of the medications becoming increasingly ineffective, experts warn.
‘This problem has been bubbling up over the past five years and now we’re at a point where these hard-to-treat infections are becoming commonplace,’ says Professor Darius Armstrong-James, an infectious disease expert at Imperial College London. ‘Patients often need to use multiple applications of terbinafine. This is the case in around a third of cases.’
Drug-resistant infections might respond to stronger prescription antifungals or combinations of these drugs used simultaneously and for long periods. However, these treatments sometimes cause unpleasant side effects including bowel problems and nausea.
Prof Armstrong-James classes a ‘significant’ number of his patients as ‘untreatable’ – meaning they have to use antifungal medications almost continuously to keep their infections under control.
Like bacteria, fungi, a category of organisms that includes yeast and mushrooms, can evolve to develop stronger defences against drugs designed to kill them. And the over-use of antifungal drugs can speed up the development of hard-to-treat strains.
Experts point to the heavy use of antifungal pesticides in the food industry, which protect fruit and vegetables from being spoiled by fungal infections.
‘This creates the perfect conditions for drug-resistant strains of fungus to form,’ says Prof Armstrong-James.
‘These then make their way into animals and humans.’
The overuse of antifungal medicine is also driving the problem.
‘Patients will keep going back to the pharmacy to get more terbinafine, even if it is not working, or they’ll stop taking the treatment before the course is finished,’ says Dr Neil McCarthy, a fungal infection expert at Queen Mary University of London. ‘This allows the fungus to build up resistance.’
Experts say one possible solution is to ensure all antifungal treatments are prescribed by a doctor.
‘A clinician could take a sample of the infection and test it in a lab to see whether it is already resistant to terbinafine before offering the treatment,’ says Dr McCarthy.
In 2014, scientific advisers to the European Commission suggested removing antifungal treatments from cosmetic products, like dandruff shampoo, to slow the growth of drug-resistant fungus, but this has not yet happened.
Ultimately, experts say the key is to develop new medications.
‘There are only a small number of new treatments coming through for athlete’s foot,’ says Prof Armstrong-James. ‘If we don’t quickly focus more research into this field, we will soon be in a position where millions of Britons are experiencing very uncomfortable, debilitating and recurrent skin infections.’