The Vale Clinic

Part I: Why does the Underside of Toenails Smell bad?

I came across this question, whilst browsing, ‘why does the underside of toenails smell bad,’ I found the question intriguing, and as it is a very common problem, more than we’d like to imagine, I decided to set about answering it. 

There are several reasons why you might get a ‘bad smell’ from the underside of a toenail. In this post, I will be focusing on one very common reason, fungal nails. 

Fungal nails can give off an offensive smell if you’ve ever been brave enough to scrape the muck from underneath the nail.

In the next few minutes, I will be sharing with you –

  • What fungal infection is
  • How you can identify it
  • How and why, you develop a fungal nail infection

In Part 2, I will share how fungal skin and nail infections can be treated, and managed.

If you’ve decided it sounds all too gruesome at this point, you might want to STOP reading here, but if you want to get down to the nitty-gritty about nasty horrible fungi, continue reading, you’ve been warned! mind you some fungus are friendly fungi – mushrooms.

What is a fungus?

Fungi are organisms found in the soil, air and in the water around us, and as a result, infections can start on the skin or in the lungs.

Fungi live on dead tissue, skin, nails and hair, and multiply in warm, moist environments for example, in-between the toes or underneath a nail.

There are different kinds of fungi which cause infection on different parts of the body, on the foot it is called Tinea Pedis which you will know as athlete’s foot. 

Majority of individuals who have recurring bouts of athlete’s foot – fungal skin infection, usually go on to develop fungal nail infection, known as Onychomycosis, quite a mouthful.

Fungal nails are caused by yeasts, moulds or dermatophytes that live off the protein on the surface of the skin. Dermatophytes being the most common one to cause fungal nail infections.

How can I tell, I have a fungal skin or nail infection?

Athlete’s foot can be caused by different strains of fungi, Trichophyton, Epidermophyton or Microsporum; and therefore, look different in presentation.

On the sole of the foot, heels and toes, It can appear as

  • dry scaly or flaking patches of skin
  • red spots, sometimes filled with pus.
  • moist areas in-between the toes, most especially the little toe.

Fungal nails are not pleasant to look at, in most cases the nail has a white to yellowish discolouration on the surface of the nail, you can have a  crumbly chalky texture – like the toenail in the picture above, or the cream or black/greenish discolouration of soft sticky mash underneath the nail – this is where the smell usually comes from.  The thickness of the nail can vary from normal to excessively thickened. 

Analysing the physical appearance of the nail can only serve as an indication of fungal infection; backed with the observer’s experience – in this case, a Podiatrist, a more accurate diagnosis can be reached. 

However, to be absolutely sure of a clinical diagnosis, and before you start any form of treatment, it is strongly recommended a lab test ( mycology test) is requested.

A mycology test can be requested through your GP to confirm a diagnosis. Lab tests, on average, can take up to six weeks.  An initial report is usually available after two weeks, and the final report at six weeks. 

More recently, tests that can be performed on the spot in a clinical setting, are readily available to practitioners. This significantly reduces the time it takes from diagnosing the nail infection, to starting a treatment of choice.

How does it develop, and why?

According to research, fungal nail infection affects between 2% and 8% of adults in the western world.  The cause for developing fungal nail infections can vary from person to person. 

The most common reason is the presence of athlete’s foot which may well have been long- established on the skin, accompanying damage to the nail. 

Running a marathon is a good example of a sport related activity that can lead to damage to the nail. The nail can be damaged through repetitive injury to the nail in the shoe, weakening the nail plate, rendering it vulnerable to infection.

There are other reasons and conditions that can increase the possibility of developing a fungal nail infection, these include:

Most fungal skin and nail infections are treatable, however, with that said, it will require a lot of patience, perseverance and persistence ( I call it the 3 Ps) on the part of the individual.

Join me in the next post, where I will be exploring how fungal skin and nails can be treated and managed.


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