Intralesional corticosteroids involve the direct injection of a steroid medication into a skin lesion. This delivers a concentrated dose of medication precisely where it is needed. The primary goal is to improve the appearance of the treated area and reduce symptoms like itching or pain. Triamcinolone acetonide, often called “intralesional triamcinolone,” is the most frequently used steroid in this therapy.
Conditions Treated with Intralesional Corticosteroids
Intralesional corticosteroids manage various skin conditions, particularly those characterized by inflammation or excessive tissue growth. This method offers advantages over topical creams by delivering medication to deeper skin layers and over oral steroids by minimizing systemic effects.
Keloids and Hypertrophic Scars
Keloids and hypertrophic scars are raised, thickened scars that develop after skin injury. Injections help flatten and soften scar tissue by reducing inflammation and inhibiting collagen overproduction, a protein that contributes to scar formation.
Alopecia Areata
Alopecia areata is an autoimmune condition causing patchy hair loss. Corticosteroids injected into scalp lesions suppress the localized immune response that attacks hair follicles, encouraging hair regrowth.
Cystic Acne
For severe, inflamed cystic acne, intralesional corticosteroids rapidly reduce inflammation, pain, and swelling. The injection helps shrink the cyst and prevent scarring by calming the deep-seated inflammatory process.
Psoriasis
Localized psoriasis, a chronic autoimmune skin condition, benefits from these injections. Corticosteroids reduce rapid skin cell turnover and inflammation characteristic of psoriatic plaques, leading to their flattening and resolution.
The Injection Procedure
The intralesional corticosteroid injection is typically performed in a clinical setting by a healthcare professional, usually a dermatologist. No special preparation is generally required before the appointment.
Before the injection, the treated skin area is thoroughly cleansed with an antiseptic solution to minimize infection risk. A very fine needle is used for the injection.
The medication is injected directly into the skin lesion, often into the mid-dermis layer. Patients commonly describe the sensation as a brief pinch or sting. Depending on the size of the treated area, multiple injections may be administered during a single session. The entire procedure is quick, completed within about 15 minutes. After the injection, a small dressing may be applied, which can be removed after a few hours.
How Intralesional Corticosteroids Work
Corticosteroids are anti-inflammatory agents that mimic hormones produced by the body’s adrenal glands. Injected directly into a skin lesion, they deliver a high concentration of medication to the affected site. This direct delivery bypasses the outer layers of the skin, which can sometimes be thickened by the condition, ensuring the medication reaches its target effectively.
Once in the tissue, corticosteroids reduce local inflammation and suppress an overactive immune response. For conditions involving excessive tissue growth, such as keloids and hypertrophic scars, these steroids also inhibit the activity of fibroblasts, which are cells responsible for producing collagen. This inhibition helps to soften, flatten, and shrink the scar tissue over time. The localized application means that very little of the steroid is absorbed into the bloodstream, thereby minimizing systemic effects.
Potential Side Effects and Aftercare
While intralesional corticosteroid injections are generally considered safe, some side effects can occur, mostly at or near the injection site. Immediate effects may include mild pain, bleeding, or bruising. A rare risk is local infection, which could lead to an abscess.
Longer-term side effects involve changes to the skin’s appearance. Skin atrophy, or thinning, may manifest as a slight indentation or dimple at the injection site, and can occasionally be permanent. Changes in skin pigmentation are also possible, leading to hypopigmentation (lightening) or, less commonly, hyperpigmentation (darkening) of the treated area. Visible small blood vessels, known as telangiectasias, can also develop at the injection site.
After the injection, keep the treated area clean and dry. Patients should avoid manipulating or rubbing the injection site for several hours to allow the medication to settle and reduce irritation. If there is persistent pain, increasing redness, swelling, warmth, or any signs of infection, contact the healthcare provider. Multiple treatment sessions, typically spaced several weeks apart, are often necessary to achieve optimal results.