Give a brief definition of verruca pedis. (1)

b) A patient presents with a large single verruca on the plantar aspect of the right

heel. Outline the advantages and disadvantages of three (3) different treatment

strategies which could be employed for the treatment of this condition. (9)

Give a differential diagnosis between a vascular corn, heloma durum and a verruca pedis.

Describe the pathological changes that occur in (or in the tissues) verucca pedis.

Definition

Verruca pedis is a wart/non- cancerous tumour which is found on the foot, mainly on the plantar surface. Verrucae are caused by the Human Papilloma Virus (strains 1, 2 and 4). This is a DNA containing virus and is found in the stratum spinosum layer of the epidermis. It can be transmitted through direct contact and direct inoculation, i.e. via cuts, fissures, callus. The injury to the skin usually takes place during barefoot activities, for example, when swimming. The incubation of the HPV virus is variable – ranging from 1-20 months. Other conditions which are

The aim of any treatment for VP is to destroy the infected cells. However, debate still remains over whether or not to treat VP. Spontaneous resolution of verruca pedis can occur. Common treatments include Keratolytic agents, Laser therapy, Curettage, Cryotherapy and Electrosurgery. Other treatments include Occlusive dressings.

The aim of a keratolytic treatment is to destroy the infected tissue and bring about separation of the necrosed area after treatment. This treatment is contraindicated in areas with very little adipose (fatty) tissue.

The overlying callus is debrided and keratolytic agents such as salicylic acid (in paste form - between 30%-75%) and monochloracetic acid (saturated solution) are applied after the normal surrounding skin has been masked off. Patients should return within 7 days. The destroyed tissue is removed under strict antiseptic conditions. A further application of the agent is applied if required, or if the lesion has become necrotic or ulcerated, a sterile dressing may be applied. The ulcer is then managed until it has healed. The advantages of this treatment are minimum disability, no anaesthesia required, minimal discomfort, and a low risk of scarring. Disadvantages include prolonged treatment times, differing cure rates and recurrence of lesions.

Cryotherapy results in necrosis of the tissue resulting in the formation of a blister with an ill-defined bluish periphery. The most common agent used in this treatment is liquid nitrogen. The overlying callus is debrided, liquid nitrogen is then applied via a cotton bud. Sterile dressings are then applied. The advantages of this treatment are minimal discomfort and scarring, no need for anaesthesia and fewer treatements required. The disadvantages have included considerable pain and scar formation.

Curettage. A local anaesthetic is administered. The VP is circumscribed with a 15 blade. The VP is removed using a spoon curette. The base electrocauterised to control bleeding points. The base is phenolised. The ulcer is then managed until it has healed. Advantages, some professionals believe that this is the most beneficial treatment. Disadvantages - recurrence, poor or painful scar formation, ulcerations, new eruptions and delayed healing.

Low level laser therapy has 3 effects: healing growth factor response through increased ATP and protein synthesis, and improved cell proliferation. Pain relief through increased serotonin and increased endorphin release. Immune system support through increasing levels of lymphocyte activity. The advantages of laser are decreased discomfort and post operative complications. Faster healing and decreased recurrence. Disadvantages include the formation of scar tissue, sterile abscesses, osteomyelitis and recurrence of lesions.

Differential diagnosis (between a corn and a verruca)

A corn is often singular, whereas there can be multiple verruca on the foot. With verrucae the skin striations are interrupted and in a corn they are continuous. Verrucae contain thrombosed capillaries which show as black specks on the skin. Corns do not have thrombosed capillaries, however extravasation may also present as a black stain. Verrucae can occur anywhere and corns usually appear on high pressure areas. Verrucae can be painful when lateral pressure is applied. Whereas corns are very painful on direct pressure. Verrucae often develop rapidly and corns develop over time. Verrucae tend to occur most often in children and young patients, whereas corns are more likely to be found in older patients. On reduction, verrucae bleed freely because of superficial capillaries. With corns there shouldn't be much bleeding except in the case of vascular corns.

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University Pod Year 1 Notiz am Verrucae, erstellt von Morgan Morgan am 16/04/2014.