Virtually all medicines for the skin are topical or systemic. The topical medicines are applied directly into the affected area of the skin. The systemic drugs are ingested orally or injected and distributed throughout the body. On rare occasions, when you need a high concentration of a drug in the affected area, the doctor may inject a drug just under the skin, this procedure is called intradermal injection.

Some medicines for the skin require a prescription, others can be purchased without a prescription. Although generally are considered safer than those that require a prescription, OTC medicines should be used with caution. Implementing the wrong medication can worsen a disease skin or hide symptoms, making diagnosis more difficult for the doctor.

Topical preparations
The active substances (drugs) from a topical preparation are mixed with (suspended in) a vehicle (an inert carrier of the medication). . Consequently, among the topical preparations, the formulation and consistency vary widely. It is the vehicle that determines the strength of the product and makes the active compounds remain on the surface or penetrate the skin (if the preparation is thick and oily and watery or light). Depending on the vehicle used, the preparation will be an ointment, cream, lotion, a solution, a powder or a gel.

Ointments, which contain a large amount of oil and very little water, have a greasy appearance and are difficult to wash. Ointments are more appropriate when the skin requires lubrication or moisture. While its use is more cumbersome that preparations with water-based creams, ointments are more effective in providing active ingredients to the skin.

The creams, which are the most commonly used preparations are oil in water emulsions. They are easy to apply and give the feeling of disappearing scrub on the skin.

Lotions are similar to creams but they contain more water. They are in fact suspensions of finely powdered material dispersed in a water-based or oil and water. Lotions are easy to use and are particularly beneficial to the `cool or dry skin.
The solutions are liquid in which a drug dissolves. The solutions tend to dry the skin rather than moisten. Liquids are most frequently used alcohol, propylene, polyethylene and running water.
The powders are dried forms of substances that are used to protect areas where skin rubs a region against another (for example, in the buttocks, between the toes, in the armpits or groin, or under the breasts ). Powders dry skin macerated (softened and damaged by moisture) and reduce friction by absorbing moisture.. Powders can be incorporated into the protective creams, lotions and the ointments.

The gels are water-based substances with a thickened without oil or fat.The skin does not absorb the gels as well as preparations containing oil or grease.