Intralesional injection therapy (IIT) is an established treatment modality that allows for the percutaneous administration of medicines into pathologic skin lesions. In the past, IIT was used primarily to inject corticosteroids into psoriatic lesions or hyperactive scars; but in recent years IIT has proven useful in the percutaneous injection of other nonsteroidal agents such as bleomycin, fluorouracil, methotrexate, and chloroquine.
The administration of medicines into the center of a dermatologic lesion increases the local dose-concentration of the pharmaceutical agent, while obviating the need for systemic drug administration. In the case of corticosteroids, IIT also provides an effective depot of drug within the lesion, thus decreasing the interval frequency of administration.
Despite the obvious benefits of IIT, certain drawbacks pose limitations to its use. The most commonly encountered limitations include pain on administration, an inability to inject within the lesion, and extravasation of drug into surrounding soft tissue.
Many of the drawbacks of IIT administration can be offset by the adoption of simple clinical strategies that can reduce patient discomfort, improve efficacy, and reduce short- and long-term complications.
Pain: Strategies to counteract patient discomfort during IIT injection include pretreatment application of ice, topical cryo-cooling, topical lidocaine anesthetic, infiltrative lidocaine injection, and application of lidocaine tape. Topical anesthetic administration has an inherent limitation in keloid therapy because the pain of injection is often caused by injection of the needle into the overlying skin, as well as the pain caused by manipulation of the inflammatory keloid. The reduction of patient discomfort is crucial in treatment and in the maximizing compliance with therapy.
Nodular density: Often, pathologic processes such as keloids, hypertrophic scars, foreign body reaction, metaplastic nodules, and granulomas can present as extremely dense lesions that present a challenge during injection. Dense nodular lesions are often difficult to inject with small or large gauge needles, making it almost impossible to successfully administer a medicine into the center of the lesion. Strategies to counteract this problem include 1 of 2 approaches: (1) delaying IIT for at least 1 week and advising patients to perform mechanical massage techniques to soften the lesion prior to injection; and (2) intralesional injection of hyaluronidase alone or in combination with therapeutic injections.
Extravasation: Lastly, it is imperative to avoid improper placement of the pharmaceutical agent to avoid extravasation of medicine into the perilesional tissue. Improper injection techniques in the setting of corticosteroid therapy may lead to atrophy, the development of telangiectasia, and contour deformities of the soft tissue. Strategies to avoid this problem include lower dose administration of medicines until the lesion softens, mechanical softening of the lesion with massage (important for keloids, thick scars, granulomas, and foreign body reaction), and use of smaller gauge needles to avoid inadvertent administration of medicine into the perilesional space.
IIT is an important therapeutic technique in the management of common dermatologic disease processes, including keloids, scar tissue, metaplastic nodules, and granulomas. Simple techniques to minimize patient discomfort, improve efficacy, and reduce extravasation can improve results and reduce the complication profile of IIT.
Raffy Karamanoukian, MD, FACS
Santa Monica, CA
Nazareth Papazian, MD
Hratch Karamanoukian, MD, FACS
Dr. Barankin is a dermatologist in Toronto, Ontario, Canada. He is author-editor of 7 books in dermatology and is widely published in the dermatology and humanities literature.