Final answer:
Topical administration is the form of drug administration that involves direct contact with the skin, which can be used for local treatments or systemic absorption through transdermal patches.
Step-by-step explanation:
The form of drug administration that involves direct contact with the skin is known as topical administration. This route allows drugs to either work directly on the skin or to be absorbed through the skin into the systemic circulation. Topical medications include a variety of preparations such as creams, ointments, gels, and patches. These are often used for treating local conditions like dermatitis, psoriasis, and fungal infections, as well as for systemic delivery, as in the case of transdermal patches (for example, nicotine patches for smoking cessation or hormone replacement therapies).
Enteral administration refers to the route involving the esophagus, stomach, and small and large intestines (i.e., through the digestive tract). Drugs administered enterally are primarily oral medications but can also include those given via nasogastric or gastrostomy tubes in patients who cannot swallow. Parenteral administration, on the other hand, bypasses the digestive system entirely, including routes such as intravenous (IV), intramuscular (IM), or subcutaneous (SC) injections.