Intradermal Injection

Intradermal injection is a type of drug or vaccine administration that is performed directly into the layer of skin called the dermis. This type of injection is used for certain specific purposes, such as allergy testing or administration of certain vaccines, such as the tuberculosis vaccine (BCG).

The technique of administering an intradermal injection involves inserting a very thin needle, typically 25 to 27 gauge, at a very superficial angle into the skin, almost parallel to the surface. This is done to ensure that the medication or vaccine is properly deposited in the dermis, which is the layer of skin where the cells responsible for initiating the immune response reside.

A distinctive feature of intradermal injection is the formation of a small bump or "bleb" under the skin, indicating that the liquid has been successfully administered into the dermis. After the injection, a small elevation of the skin, similar to a small blister, may be seen, which will fade over time.

It is important that intradermal injections are administered with caution and by trained personnel, as incorrect technique may result in inappropriate administration of the medication or vaccine, which may affect its effectiveness or cause complications.