They consist of collections of blood vessels and appear most frequently after age 35. Although disfiguring, they do not become cancerous. They are the result of herpes simplex type 1 infections and may be activated by sunlight or fever. Cryotherapy is a treatment technique that removes tissue by spraying the skin with liquid nitrogen and causing the tissue to form a blister. As the blister heals, unwanted surface cells are shed.
Cryosurgery involves the same process, but the depth of freezing is much greater.
This technique is used to treat some skin cancers, and results in tissue destruction and wound healing with minimal scarring. Curettage and electrodesiccation is a technique in which cancerous tissue is removed under local anesthesia with a sharp surgical instrument called a curette. Electrosurgical equipment is then used to stop the bleeding and to cauterize a zone of normal tissue. Dandruff is made up of small flakes of dead scalp skin. It occurs under circumstances in which the surface skin cells of the scalp grow unusually fast.