• Introduction

    Warts & Verrucas

Warts and Verrucae (plantar warts – are a common nuisance. These are skin lesions that are caused by the ubiquitous Human Papilloma Virus (HPV). Once present they are hard to get rid of. In fact, caution is advised with repeated attempts with filing and salicylic acid and treatments that macerate the surrounding skin can cause them to spread.

These days there is little that can be done on the NHS for warts as they are classified as a cosmetic issue. Treatment will only be performed if there is an issue that prevents normal functioning of an individual.

Much confusion exists over the numerous methods of treatments of warts. So many methods are proposed but many methods are ineffective. The main reason for failure to clear warts is that if you leave behind residual wart tissue and fail to clear it fully there is a high likelihood of recurrence.

Most methods are incomplete due to failure to use anaesthetic. If maximal chance of clearance is do be obtained the tissue to be treated will have to be injected with local anaesthetic. Removal of the lesion to a deep enough level will be sore and not tolerated by an individual who has not had anaesthetic.

This is why methods such as physical paring followed by silver nitrate application and strong salicylic acid application (which are often used by chiropodists and podiatrists) are valid methods but unfortunately have a high failure rate. Numerous repeat treatments are required and most times despite repeat treatment failure to clear is commonplace.

Summary of methods with high failure rate

Veruccae have the highest rate of treatment failure and this is directly related to the extent of thickness of lesions and failure of complete clearance. I have discussed commonplace treatment modalities below and why most of them fail. Mosaic warts/veruccae are ones that are large in size due to the superficial spread of the lesions. These are more difficult to clear due to their size. Sometimes Dr Hussein will treat part of mosaic wart/verucca on the foot in order to make sure the ensuing wound is not to large and heals quickly without wound complications.

Periungual warts (warts that affect the nail edges) also have a high fail rate. This is more to do with the fact that because the wart affected tissue wraps tightly around the nail fold and under the nail. As a result, it is very hard to clear it completely without temporarily or sometimes permanently causing some form of nail growth deformity. Sometime growth of warts around the nail have already caused some form of nail growth deformity before treatment.

Silver Nitrate/Salicylic Acid (50% strength)

Paring followed by silver nitrate application and strong salicylic acid application (which are often used by chiropodists and podiatrists) are valid methods but unfortunately have a high failure rate. Numerous repeat treatments are required and most times despite repeat treatment failure to clear is commonplace. This because silver nitrate and strong salicylic preparations penetrate the top millimetre or so of a lesion that can be potentially up to 5mm plus in thickness. This leaves the majority of the lesion still present. As a result, it would be evident from the start that the treatment was doomed to fail.

Cryotherapy (Liquid Nitrogen – freeze therapy)

This is a more effective treatment but still has a high failure rate. It is used by GPs and Dermatologists. Liquid nitrogen is relatively inexpensive and readily available within the NHS. However, these treatments are now not reimbursed by the NHS to GPs and dermatology departments. As a result, it is rare to find a GP surgery that offers this treatment on a non fee-paying basis.

Freezing the wart with liquid nitrogen is painful. However it is an effective way of killing wart tissue. The problem is that local anaesthetic is not used during freezing. This is because the local anaesthetic solution can freeze itself and the doctor uses pain as an indication as to how far he can safely freeze.

Unfortunately, the treatment often fails on the soles of the feet due to wart thickness. Before the full thickness can be treated the patient finds the treatment too painful and will not tolerate enough freezing. If a pulsed application of the freezing spray is used the freezing will not be deep enough as the tissue warms up again between each pulse.

It is impossible for the doctor to tell whether or not the wart has been frozen to an appropriate depth and also usually the patient would find a deep enough freeze too painful.

Despite many repeat freezing attempts recurrence or regrowth of the wart is common.

Needling

This is a method that has gained popularity over the past few years. It is designed to push wart affected tissue deeper into the skin with small needle punctures. The theory behind it is that by doing this the skin’s own immune defence system is triggered and will fight off the wart spontaneously. Even though this seems like a good idea the reality is that the rate of failure of this treatment is high. There is not much clinical evidence to support its use.