The Vale Clinic

Part 2: Why does the Underside of Toenails Smell bad? Treatment and Management

Fungal skin infection and most fungal nail infections can be treated and managed effectively, in this post, I will be exploring just how this can be done.

Here’s recap of what fungal skin and nail infections are from Part I ‘Why does the underside of toenails smell bad?’


         Fungal skin infection known as Athlete’s foot, can be caused by different types of fungi, and therefore look different in presentation.  It can appear as dry scaly or flaking patches of skin, as red itchy spots sometimes filled with pus, and on other occasions, as moist areas in-between the toes.  All these, can also occur at the same time, on the same foot.

     Fungal nails are caused by non- dermatophytes (yeasts, moulds) or and dermatophytes that live off the protein on the surface of the skin.  In most cases the nail has a white to yellowish discolouration on the surface of the nail.

Underneath, the nail can present as a chalky crumbly texture with brown or black discolouration; streaking within the nail and lifting of the nail from the nail bed is possible.

Fungal nail infection or onychomycosis (Tinea unguium) accounts for approximately 50% of nail conditions.  It is more common in toenails than fingernails, and can present in four main patterns. 

First of all, to help with a bit of terminology, below is a labelled diagram showing he different parts of the nail.



Figure 1: Structure of the nail




Distal -Lateral Sub-ungual Onychomycosis (DLSO)
This is the most common pattern of infection.  The fungus infects the nail from the underside of the nail, and can be caused by any of the organisms – dermatophytes and non-dermatophytes.  The infected nail can vary in colour from brown to black, and can be associated with lifting of the nail, from the nail bed.

Figure 2: DLSO


Superficial Onychomycosis (SO)
Here, the fungus infects the surface of the nail, causing Islands of white discolouration or grooves in the nail.

Figure 3: SO

Total Dystrophic Onychomycosis (TSO)
The whole nail plate is affected, and is characteristic of severe nail infection.  This is usually observed in the latter stages of fungal nail infections, where the nail is thickened and crumbles away.  TSO is caused by different organisms.

Figure 4: TSO
(credit rock- café.info)

Proximal Sub-ungual Onychomycosis (PSO)
This is a rare form of fungal nail infection, and can prove difficult to treat. The infection starts from the half – moon shape at the base of the nail called the lunula.  It is commonly seen in individuals with a suppressed immunity.

Figure 5: PSO

Why should I treat it?

Fungal nail infection can have a significant effect on the quality of life, it can be a source of embarrassment and have a debilitating effect on self-image.

Onychomycosis is common in the elderly, individuals with a lowered immunity, poor circulation and diabetes.

In individuals with lowered immunity or chronic diseases such as Diabetes and poor circulation, it can lead to secondary bacterial skin infection known as cellulitis.  

Fungal infection can potentially spread to other parts of the body – hands, groin or torso if left untreated.

Treatment of fungal infections should therefore not be seen as a cosmetic condition discounting the need for treatment, but should be assessed on an individual basis.

Not all individuals will be eligible for treatment.  Eligibility is based on the individual’s health status and suitability to treatment available. The attending clinician will take a thorough medical history to form a basis of whether treatment should be considered.

Below are some questions to be explored when considering treatment –

Is the nail uncomfortable or painful?

Is the appearance of the nail causing embarrassment to the individual?

Is it a potential or likely cause of recurrent skin infection? (especially in individuals with poor circulation or diabetes where their health may be compromised)

Is the individual suitable for any of the proposed treatments?



How do I treat it?

Clinical diagnosis of fungal nail infections should be done in conjunction with laboratory findings prior to treatment.  Once the causative organism/s are known, treatment can be better targeted.  This reduces the risk of unnecessarily creating a huge dent in your bank balance, and save time on your part, as treatments can take several months.

Treatment modalities for fungal nails are systemic or topical preparations.  Systemic agents come in the form of medicines, and topical agents that can be applied directly to the nail – a paint/lacquer or solution. 

Treatment should only be started after consultation with a healthcare professional or general practitioner.

The severity of fungal nail infection is classified depending on the percentage of nail affected, this is simply a guide.

Mild – less than 40% of the nail is affected

Moderate – 40 to 70% affected

Severe– the whole nail is affected

A typical scenario of  the process when diagnosing a fungal nail infection is as follows:

  • An individual attends clinic with a suspected fungal nail infection

  • The Podiatrist confirms clinical evidence of a fungal nail infection, and in some cases accompanying fungal skin infection

  • Nail clippings are taken from the infected nail, and sent  to the laboratory for testing to confirm or discount clinical findings  

  • Positive laboratory result, start treatment-

    Mild to Moderate infections – The Podiatrist may consider recommending the use of topical treatments or other treatment options such as phototherapy using low laser therapy.

    Moderate to severe infections -The Podiatrist may consider referring on for systemic medication by careful selection of the patient, plus the use of topical treatment.  Nail removal ( under sterile conditions with local anaesthetic) and treating the nail bed  with an anti-fungal agent afterwards, may also be considered.

  • Negative laboratory result

    Review in clinic with Podiatrist to determine other possible causes of nail damage, and or refer for further investigation/opinion if  indicated.

    It is recommended that any existing fungal skin infection is treated, when starting treatment for fungal nail infections.  Check other family members for fungal infection, and have them treat any infections at the same time.

    Athletes foot can be treated with fungicidal creams and sprays – Lamisil is an example.  Follow the manufacturer’s instructions on use, or as directed by your prescriber. Most preparations are applied daily, and some once a week.

    Lamisil Once is used once, and over the course of seven days the active ingredient is delivered into the skin killing the fungus. Results are seen very quickly, usually within a few days.  

    To prevent recurrence of fungal skin infection, follow these basic tips

    • Wash your feet daily, and dry well particularly in-between toes
    • Wear 100% cotton socks, if possible, replace existing ones
    • Wash socks and towels on a hot wash, 60 degrees
    • Choose footwear made from breathable materials, if possible, replace existing ones
    • Spray shoes before and after wear, with an anti-fungal spray
    • Alternate your shoes to allow them to air
    • Use an anti-fungal cream once or twice a month as a preventative measure- if you suffer with frequent bouts
    • Protect feet in shared bathing areas
    • Keep your feet dry throughout the day
    • Maintain and improve health and chronic conditions (for example – stop smoking, manage diabetes adequately)


    How can I prevent fungal nail and skin infection?

    After successful treatment of fungal nail and skin infection, the possibility of recurrence is high as a result of the type of lifestyle we live, for example swimming, gym visits all can create the right environment to develop fungal infection in the feet.

    Fungal elements can remain in our immediate environment,  in shoes and socks creating a reservoir and source of re-infection.

    It is therefore important to make sure we unburden our immediate environment of fungal elements by adopting an effective cleaning routine, and treating socks and shoes with anti-fungal agents, or replacing them where possible.

    To reduce the risk of relapse, practise good foot care habits, and follow these simple steps below. 

    • Treat any signs of Athlete’s foot early.
    • Avoid going barefoot in public places.
    • Dry feet properly after bathing.
    • Check there are no other active sources of infection elsewhere i.e. hands, groin, torso.
    • Discard old footwear and socks.
    • Avoid tight fitting socks and shoes.
    • Change your socks daily, wear breathable cotton socks.
    • Keep nails short, clean and dry. This helps prevent infectious organisms from collecting under the nail
    • Ensure other family members are free of fungal skin infection.
    • Sanitise instruments used for nail care by sterilisation after each use
    • Use of a nail lacquer twice a month as a preventative measure, has been shown to reduce the risk of relapse
    • Visit a Podiatrist or general practitioner for advice and guidance on treatment and management if there is any evidence of recurrence

      Book an appointment today with Ronke the podiatrist, or call The Vale clinic on 07988 916 198 if you would like more advice, or to find out more about treatments offered for fungal nail infections.

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