30 HOW TO TREAT : PRACTICAL PROCEDURES IN DERMATOLOGY
30 HOW TO TREAT : PRACTICAL PROCEDURES IN DERMATOLOGY
11 OCTOBER 2024 ausdoc . com . au
Figure 3 . Right anterolateral thigh skin cancer marked for surgical excision . The histopathology report confirmed a nodular BCC . The patient had an extensive history of non-melanoma skin cancers , and background photodamage is evident on the leg . in response to pressure or friction . However , unlike a wart , a plantar corn or callus will have the normal skin lines continuing on their surface and lack the characteristic black dots of thrombosed capillaries .
Biopsy result
Cutaneous warts are usually diagnosed clinically . Skin biopsy is sometimes required for atypical appearing warts where there is suspicion of skin cancer . The hallmark histopathological feature is a papillomatous epidermis composed of hyperplastic epidermal cells , contributing to their verrucous or cauliflower-like appearance . 35 Other features include acanthosis , hyperkeratosis and vacuolated keratinocytes known as koilocytes .
Treatment options
Treatment is not necessary in all cases and depends on the location , symptoms and patient ’ s preference . In fact , two-thirds of warts in children will resolve spontaneously without treatment within two years . 36 In adults , spontaneous resolution tends to be slower and may take up to several years . The principle of treatment is to remove the virus-containing skin cells rather than kill the virus itself . Recurrence of warts is a common challenge and can occur despite successful initial treatment . 37
TOPICAL TREATMENT WITH SALICYLIC ACID OR PODOPHYLLIN Topical treatments are first-line options given their convenience , efficacy and minimal side effects . Topical agents include salicylic acid , podophyllin and cantharidin . A practical guide for the in-office application of cantharidin appears in box 3 .
Salicylic acid is a keratolytic agent that works by disrupting the intercellular connections between keratinocytes , leading to breakdown of the keratinised outer layer of the wart . 38 To increase efficacy , the wart can first be softened by soaking in hot water and the surface exfoliated with a pumice stone or emery board to remove hyperkeratotic debris . After drying , wart paint , paste or other formulations containing salicylic acid in concentrations of 10-40 % can be applied directly to the wart once daily , for up to 12 weeks . Rates of success vary greatly , and efficacy can be increased with proper patient education on application techniques . 39
Podophyllin is an anti-mitotic agent derived from the roots of the podophyllum plant . It is more commonly used for genital warts . 40 Because of its potential toxicity , podophyllin should be used with caution and only as directed . Generally , the cream or solution is applied with a cotton-tipped applicator to the wart twice daily for three consecutive days . The treatment can be repeated every week for a maximum of five weeks . Side effects include local irritation , burning and erythema . Furthermore , podophyllin is contraindicated in pregnant women because off the risk of teratogenicity . 41
CRYOTHERAPY Cryotherapy with liquid nitrogen is a commonly performed treatment for cutaneous warts . There is mixed evidence of its effectiveness in the literature , with some quoting cure rates of 14-90 %, although one 2011 systematic review found that it was no better than placebo . 42 Treatment should be repeated every 1-2 weeks for up to 3-4 months . Further details on the practical considerations for cryotherapy are discussed earlier .
CURETTAGE AND CAUTERY Superficial skin surgery with C & C may be used for large and resistant warts that have failed topical treatment . However , recurrence rates of up to 30 % have been reported . 43 Warn the patient that the treatment may leave a permanent scar . A practical guide to C & C is outlined in box 2 .
CANTHARIDIN Cantharidin , also known as “ beetle juice ” and derived from blister beetles , is the favoured treatment . It is a potent vesicant that works by
Box 2 . A practical guide to curettage and cautery
• Preparation and marking : — Following informed medical consent , clean the lesion and surrounding skin with an antiseptic solution . — Dermoscopic examination of the lesion while stretching the skin can help to identify its borders . — Use a surgical marker to outline the margins .
• Anaesthesia : — Infiltrate the marked area with 1 % lignocaine and 1:100,000 adrenaline to achieve local anaesthesia .
• Curettage : — Apply gentle pressure and scrape away the abnormal tissue with the blunt edge of a 3-4mm curette , passing from the periphery to the centre of the lesion each time . — This process should be repeated in multiple directions . — As the blunt curette scrapes against healthy dermis , it produces a distinctive scraping or grating sound that provides audible feedback to help delineate the tumour . — Furthermore , only abnormal tissue will yield to the scraping of the curette .
• Cautery : — The main purpose of cautery is to destroy the remaining abnormal tissue , with a secondary benefit of providing haemostasis . — The high-frequency electrical current of the hyfrecator ( usually set to 6-7mV ) generates heat that destroys the remaining dysplastic cells and helps to ensure complete clearance of the lesion . — The hyfrecator electrode is applied to the entire surface of the lesion methodically , with a 1-2mm surrounding margin . — Care should be taken to avoid excessive cauterisation , which can cause injury to underlying structures and increases the risk of hypertrophic or keloid scarring .
• Repeat cycle : — This process of curettage and cautery is repeated for two or three cycles .
• Postoperative care : — Apply a surgical dressing to protect the wound and assist with healing . — This should remain in place for at least 24-48 hours . — The wound generally takes approximately 2-3 weeks to heal , leaving a scar that will be initially erythematous but improves in appearance over several months . — Provide the patient with wound care instructions , advice on appropriate analgesia and potential warning signs for infection or complications . A written handout is often helpful .
• Pathological evaluation : — Place the removed specimen in formalin and submit for histopathological examination .
• Follow-up : — Schedule a follow-up appointment to monitor wound healing and discuss histopathology of the lesion for
7-14 days . — Educate the patient on the importance of sun protection and regular full skin examinations .
inducing the formation of blisters within the epidermis , leading to desquamation of the lesion . 44 It also contains inflammatory mediators that help stimulate the immune response to target the wart . It is contraindicated in pregnant or breastfeeding women .
It can be used in children aged two years and older .
CASE STUDIES
Case study one
LISA , a 48-year-old lawyer , presents to her GP for a routine full skin examination . She lives by the beach and loves to swim in the ocean .
Lisa states she is now consistent with sunscreen application but remembers having a few severe blistering sunburns as a teenager , and she also used solariums on a couple