Final answer:
A medication applied directly to the skin is known as a topical medication. They can consist of creams, ointments, or lotions, and are useful for localized treatment of skin conditions or delivery of medication through the skin into the bloodstream.
Step-by-step explanation:
The term for a medication applied directly to the skin is topical medication. Topical medications include a variety of formats such as creams, ointments, gels, and lotions, which are used to treat conditions like skin infections, inflammation, and rashes.
These preparations function under the principle of selective permeability, allowing certain medicines to penetrate the skin and enter the bloodstream or to provide localized treatment on the skin itself. As an example, a topical corticosteroid cream containing hydrocortisone reduces inflammation by decreasing the secretion of histamine and suppressing the immune response locally. This helps to alleviate symptoms such as itching and rashes associated with dermatoses.
Topical medications are particularly useful when the drug is intended to have a local effect, when systemic treatment is unnecessary, or when oral administration is not feasible for various reasons. The topical route of administration can be both convenient and effective, depending on the required therapeutic outcome.