What does "intradermal" refer to in terms of administration?

Intradermal refers specifically to the administration of substances directly into the dermis of the skin, which is the layer located just beneath the outer epidermis. This method of delivery allows for a localized immune response and is often utilized for allergy testing, smallpox vaccination, and tuberculin skin tests. The dermis is rich in blood vessels and immune cells, allowing for effective absorption and reaction to the administered substance.

Other methods of administration, such as intravenous (into the bloodstream) or subcutaneous (under the skin), do not involve the dermis directly and utilize different techniques and effects. Therefore, the understanding of intradermal administration is crucial in veterinary practice for diagnosing allergies or certain conditions through skin tests.