Aldara cream contains the active ingredient imiquimod, which is a type of medicine called an immunomodulator. It is used to treat three different skin conditions: genital warts, small superficial skin cancers and actinic keratoses.
Imiquimod acts by stimulating the body's own defence mechanisms. It is thought that it works by binding to immune cells in the skin, causing them to release natural defence chemicals called cytokines. One such cytokine is called alpha interferon.
Alpha interferon and other cytokines have many functions in the immune system. They help fight viral infections by preventing viruses from multiplying in cells. They also prevent abnormal or malignant cells from increasing in numbers.
Genital warts are caused by the human papilloma virus (HPV). This cream stimulates the body to attack the virus, which cures the warts.
Superficial (non-malignant) skin cancers called basal cell carcinomas occur when certain skin cells multiply in an abnormal and uncontrolled way. This cream stimulates the body to attack the abnormal cells, which shrinks the cancerous growth.
Actinic keratoses are rough areas of skin caused by sun damage over many years, eg from sunbathing or using sunbeds, or working outdoors. They occur in fair-skinned people, whose skin is particularly sensitive to the damaging effect of UV rays. The skin lesions are usually harmless, however about two percent will turn into a skin cancer (squamous cell carcinoma). Some small actinic keratoses may disappear on their own. However, the chance of an actinic keratosis turning into a skin cancer falls if the actinic keratosis is treated early. This cream stimulates the body to attack the abnormal or damaged skin cells.
For warts on the genitals and around the anus, the cream should be applied in a thin layer to the warts and rubbed in until it vanishes, three times a week (for example monday, wednesday, friday) before going to bed. The cream should be left on for 6 to 10 hours each time and then washed off with mild soap and water. The treatment is continued until the warts are cleared (up to a maximum of 16 weeks per episode of warts).
For basal cell carcinomas, sufficient cream should be applied to cover the treatment area, including one centimetre of skin surrounding the tumour, and rubbed in until it vanishes five times a week (for example monday to friday) before going to bed. The cream should be left on for 8 hours each time and then washed off with mild soap and water. The treatment is continued for 6 weeks. 12 weeks after the treatment is finished your doctor will reassess the cancer. If it has not fully responded a different treatment will be used.
For actinic keratoses, sufficient cream should be applied to cover the treatment area, and rubbed in until it vanishes three times a week (for example monday, wednesday, friday) before going to bed. The cream should be left on for 8 hours each time and then washed off with mild soap and water. The treatment is continued for 4 weeks and you then have a 4 week treatment-free period before your doctor reassesses your skin. If any actinic keratoses remain you will be prescribed one more 4 week course of treatment. Each treatment period should not last for longer than 4 weeks, even if you have had missed doses or rest periods in those 4 weeks.