Guidelines for cryotherapy.

ABSTRACT

Introduction: Cryotherapy is a controlled and targeted destruction of diseased tissue by the application of low temperatures. It is a simple, cost-effective, efficacious and esthetically acceptable modality for the treatment of various dermatoses. Indications It is indicated in the treatment of a wide variety of skin conditions, including benign tumors, acne, pigmented lesions, viral infections, inflammatory dermatoses, infectious disorders and various pre-malignant and malignant tumors. Facility Cryosurgery is an out patient department procedure and can be undertaken in a clinic or minor procedure room. Instrumentation and Equipment Several cryogens such as liquid nitrogen, nitrous oxide and carbon dioxide are available, but liquid nitrogen is the most commonly used. Techniques Different techniques of application of the cryogen include the timed spot freeze technique (open spray and confined spray method), use of cryoprobe or the dipstick method. The choice of the method is based on the type of lesion. The procedure is undertaken under aseptic conditions, usually without any anesthesia. The number of freeze thaw cycles needed may vary from lesion to lesion. It is important to know the freeze time for each condition, number of sessions required and the interval between the sessions to achieve good cosmetic results with minimal complications. Contraindications The treating physician should be aware of the absolute and relative contraindications of the procedure, such as cold urticaria, cryoglobulinemia, Raynaud's disease, collagen vascular diseases, etc. Complications While cryosurgery is usually a safe procedure, complications may occur due to inappropriate patient selection, improper duration of freezing and freeze thaw cycles. The complications may be acute, delayed or protracted. In Indian skin, post-inflammatory pigmentary changes are important but are usually transient. Physician qualification Cryotherapy may be administered by a dermatologist who has acquired adequate training during post-graduation or through recognized fellowships and workshops dedicated to cryotherapy. He should have adequate knowledge of the equipment and pre- and post-operative care. Understanding the underlying pathology of the lesion to be treated, particularly in malignant and pre-malignant lesions, is important.