Intralesional injection, the direct delivery of medication percutaneously into skin lesions, has been an important part of dermatologic therapy since 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.
This is a procedure involving the injection of a steroid solution into abnormal skin, with the aim of improving its appearance or reducing symptoms. The steroid preparation most frequently used in this procedure is called triamcinolone acetonide, and you may hear the procedure referred to as “intralesional triamcinolone”.
What is a steroid?
Steroids are naturally-occurring chemicals, produced mainly by the adrenal glands in the abdomen. There are different types of steroids, and the type most commonly used to treat skin problems is known as a “corticosteroid”.
Corticosteroids have a variety of properties, but it is their effects on suppressing inflammation and on reducing the amount of collagen in the skin that are particularly utilized in the treatment of skin conditions.
The injection of a steroid into the skin has two advantages over topical and oral steroid treatment; firstly, it will often be more effective in treating deep-seated conditions than a steroid cream or ointment, and secondly, it will have only a local effect rather than the general effects of a steroid taken by mouth.
What conditions can be treated with intralesional steroid?
The most common uses of intralesional steroid therapy are in the treatment of excess scar tissue (hypertrophic or keloid scars), acne cysts and alopecia areata (a form of hair loss). However, your dermatologist may recommend it for a variety of localized inflammatory disorders, including discoid lupus erythematosus and sarcoidosis.
What does the procedure involve?
Intralesional injection of a steroid is done as an out-patient procedure, with no special preparation involved. You should tell the doctor if you have any allergies or problems with your general health.
Although the area to be treated can be numbed with a local anaesthetic, this is not normally necessary; the discomfort associated with the steroid injection is very similar to that caused by an injection of local anaesthetic. Depending on the size of the area to be treated, a number of injections may be required. Your doctor will probably place a small dressing over the injected site, and this can be removed after a few hours. Depending on the condition being treated, you may be offered further treatment sessions, at least several weeks apart.
Intralesional steroid therapy is, by and large, a safe procedure, and will not cause you to put on weight or develop excess hair. The amount of steroid injected at any one time is small, and the risk of steroid being absorbed into the bloodstream in sufficient amounts to produce internal side effects is very low.