This chapter describes other key procedures that are used in dermatology as listed in Table 9.1.

Cryotherapy

Liquid nitrogen cryosurgery is the most common form of cryotherapy used, with temperatures reaching down to −30°C. This achieves destruction of the tissue.

The spray technique with a cryogun is easiest to use (Figure 9.1). The aim is to achieve an ice field quickly with the spray tip held up to 1 cm away from the skin surface. Freeze times vary, with 5–10 seconds used for viral warts, solar keratoses and seborrhoeic warts. Bowen’s disease, superficial basal cell carcinomas (BCC) and small squamous cell carcinomas (SCC) can be treated with 30–60 seconds and a second refreeze after thawing.

Certain tumours are not suitable for treatment with cryotherapy (e.g. morphoeic BCC, large tumours >2 cm in diameter and ill-defined tumours).

Cryosurgery is painful and so young children less than 12 years of age may not tolerate it. Local anaesthetic can be used prior and two cycles of freezing may be needed in larger areas.

Side effects include pain, large blisters and swelling. If plantar warts are treated they may limit walking for a few days. Hyper and hypopigmentation can occur in patients with darker skin and hence may need to be avoided in this group.

Laser (Light Amplification by Stimulated Emission of Radiation)

This has been used for many years in dermatology to treat vascular and pigmented lesions, scars, tattoos and increased hair growth. Laser treatments are frequently requested by patients so a basic understanding is useful.

Lasers currently used include CO₂

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