From another site:
Most topical (applied to the skin) ointments and creams exert only local effects -- that is, they affect only the area to which they are directly applied. Most creams and ointments are expensive (especially steroid products) and should be applied to the skin in as thin a layer as possible. A thin layer is just as effective as a thick layer but less expensive. Moreover, some steroid-containing creams and ointments can cause toxic side effects if applied too heavily.
Before applying the topical ointment or cream, moisten the skin by immersing it in water or dabbing the area with a clean, wet cloth. Blot the skin almost dry and apply the medication as directed. Gently massage it into the skin until the medication disappears.
If your doctor has not indicated whether you should receive a cream or an ointment, ask your pharmacist for the one you prefer. Creams are greaseless and do not stain your clothing; they are best to use on the scalp or other hairy areas of the body. However, if your skin is dry, ask for an ointment. Ointments help keep skin soft.
If your doctor tells you to place a wrap on the skin after the cream or ointment has been applied, you may use transparent plastic film like that used for wrapping food. A wrap holds the medication close to the skin and helps to keep the skin moist so the drug can be absorbed. To use a wrap correctly, apply the cream or ointment as directed, then wrap the area with a layer of transparent plastic film. Follow your doctor's directions EXACTLY, and keep the wrap in place only as long as you are told to do so. If you keep a wrap on the skin too long, too much of the drug may be absorbed, which may lead to increased side effects. Do not use a wrap without your doctor's approval, and never use one for an oozing lesion.
