Topical Imiquimod 5% cream (Aldara) is an immune response modifier (IRM) available by prescription to treat a variety of skin conditions. An IRM makes cells (i.e., monocytes, macrophages and dendritic cells that have special markers on them called toll-like receptor 7) produce a number of chemicals, which include interferon (IFN), tumour-necrosis factor and interleukins, which the immune system uses to fight ‘rogue’ or unusual cells, the type of cells found in cancers. In July 2004, the FDA approved imiquimod for superficial basal cell carcinomas, which is a certain type of skin cancer on the body, excluding the face. Imiquimod cream may cause side effects, typically at the site of application and tend to be mild to moderate in nature, although they tend to be dose-dependent. The more common reactions include pruritus, erythema, edema and discharge, papular rash, pain and tenderness. There are occasional reports of hypopigmentation or hyperpigmentation. More severe localized effects include bleeding, crusting, erosions and indurations, however these tend to occur more frequently with more intensive regimens.