Diathermy is the destruction of tissue by burning it through the heat produced by a high frequency electric current.
There are two types of diathermy – unipolar and bipolar.
Unipolar diathermy may be used by your general practitioner or specialist in their rooms, while bipolar diathermy requires a general anaesthetic.
Unipolar electrocautery or diathermy is used to remove skin warts, plantar warts, genital warts, skin tags, polyps, keratoses, some types of skin cancer and other growths on the skin (all these are known as lesions). The skin is cleaned with a water based antiseptic solution, then an anaesthetic injection is given under, into and around the lesion to numb it and prevent any pain during the procedure. This will sting for 15 to 30 seconds.
After the anaesthetic has taken effect (only a few seconds) the area is cleaned and carefully dried. Then an electric probe is placed within a millimetre or two of the lesion. Using a foot or hand control, the doctor will activate an electric current through the probe, and a spark will jump from the tip of the probe to the lesion being treated. This spark will gradually destroy the lesion.
The patient may feel a fluttering sensation on the skin, and smell burning during the procedure, but should feel no pain. If pain is felt, more anaesthetic can be given.
At the end of the procedure, the patient is effectively left with a graze at the site of the diathermy procedure. This will heal in the same way as all grazes, with a scab, that will come off after ten to 14 days. There should be only mild discomfort after the anaesthetic wears off, unless the procedure has been performed on a particularly sensitive area such as the sole, when paracetamol may be needed for a day or two.
When the graze caused by the diathermy heals, a red mark will remain, but this will usually fade to a white patch over a month or two. A scar is always left after the procedure, but the colour (red or white), size and severity of the scarring will depend on the size of the lesion treated, the position on the body, and the depth of the diathermy necessary to remove the lesion. The face will usually heal well, while the back and legs often heal poorly. A very small number of patients will develop a keloid (raised red) scar that can be gradually reduced with further treatment.
Diathermy cannot guarantee that there will be no recurrence of any wart or skin cancer after the treatment, and about one in ten warts and skin cancers may come back after months or years. Any recurrence should be bought to the attention of a doctor.