Final answer:
The direct answer is 'topical'. Topical medication is applied to the skin surface and is often used when drugs are not easily absorbed orally or when targetting local skin conditions. For systemic infections at home, the oral route is commonly used, with the parenteral route as an alternative when oral administration is not feasible.
Step-by-step explanation:
The application of medication to the external surface of the skin is referred to as the topical route. This method is commonly used for medications that work on the surface of the skin or for substances that can penetrate the skin to enter the bloodstream.
Topical administration is used for treatments such as creams and ointments for various skin conditions. The skin's selective permeability allows certain medications to be effectively absorbed into the bloodstream, without the complexities of systemic administration methods like oral or intravenous routes.
For treating a systemic infection at home, the oral route is often deemed appropriate and convenient, considering that the patient can easily administer the medication themselves. However, if the medication is not easily absorbed in the GI tract or if the patient is unable to take oral medication, then a parenteral route, such as intravenous or intramuscular injection, may be preferred. Note that parenteral administration typically requires a healthcare setting.