Intralesional injection, the direct delivery of medication percutaneously into skin lesions, has been an important part of dermatologic therapy since it was first introduced in 1961 . Intralesional injections are effective for a wide range of indications, are easily performed, and are relatively safe.

The rationale for intralesional therapy is simple: to deliver a medication directly into a specific skin lesion to treat local tissues with minimal systemic effects. The skin also serves as a reservoir, allowing medication deposited in the dermis to be delivered over a period of time, resulting in prolonged therapy while avoiding or minimizing the adverse effects of systemic therapy.