Intradermal refers to a method of delivering substances, such as vaccines or medications, directly into the dermis, which is the layer of skin just beneath the outer epidermis. This technique is often used for allergy tests and certain vaccinations, as it allows for a localized immune response and can enhance the effectiveness of the treatment. The intradermal route is typically administered using a fine needle, creating a small bump or wheal on the skin's surface. This method is advantageous because it requires a smaller volume of the substance compared to other injection methods, such as subcutaneous or intramuscular injections.