Liposuction port sites are only 3 to 5 mm punctate wounds, yet depending on the patient’s constitution and postoperative care they can occasionally evolve into a red, raised liposuction hypertrophic scar. As one of our treatment options for these postoperative scars, our clinic uses local injections of the corticosteroid Kenalog® (generic name: triamcinolone acetonide). Many patients feel uneasy when they hear the word steroid, so in this column Dr. Moriwaki explains, from a medical standpoint, the mechanism of action, dosing intervals, side effects, and the role of Kenalog injections for a liposuction hypertrophic scar relative to other treatment options.

Key Points of This Article

・A liposuction hypertrophic scar is a red, firm, raised scar that develops at port sites or at areas subjected to strong traction; unlike a keloid, it stays within the original wound margin.
・Kenalog® suppresses collagen synthesis and promotes the breakdown of existing scar tissue, and is used to flatten a liposuction hypertrophic scar.
・Injections are usually spaced 4 to 6 weeks apart, with 3 to 5 sessions producing improvement in most cases, though concentration must be tailored to the patient’s skin and scar thickness.
・Side effects include skin atrophy, telangiectasia, and hypopigmentation, so precise control of injection volume and depth is essential.
・Kenalog does not treat the general fibrosis (contracture) that follows liposuction; it targets only elevation, redness, and firm nodularity of scars.

How Hypertrophic Scars Differ From Keloids

Hypertrophic scars and keloids are frequently confused as postoperative scar problems. They may look similar but differ significantly in pathology and management. A hypertrophic scar stays within the boundary of the original wound and tends to soften and regress over time. A keloid extends beyond the original wound outline and rarely resolves spontaneously. Because liposuction port sites are only millimeter-scale punctures, most cases fall within the hypertrophic scar range unless the patient has a strong keloid predisposition. However, when repeated position changes, external pressure, or drain-tube traction are added, a localized area can rise more prominently.

What Is Kenalog® (Triamcinolone Acetonide)?

Kenalog® is a synthetic corticosteroid that, when injected locally, exerts long-lasting anti-inflammatory and antifibrotic effects. In Japan it is approved for hypertrophic scars and keloids and is widely used in dermatology, plastic surgery, and cosmetic surgery. A 40 mg/mL preparation is typically diluted with saline or lidocaine to about 10 to 20 mg/mL. At our clinic we choose the minimum necessary concentration and volume based on scar thickness, site, and the patient’s age.

Medical Mechanism Against Liposuction Hypertrophic Scar

The anti-scar effect of Kenalog® is explained through three main pathways. First, it suppresses new synthesis of type I and type III collagen by fibroblasts. Second, it relatively upregulates collagenase activity, shifting the balance toward degradation of already deposited excess collagen bundles. Third, it downregulates expression of pro-inflammatory and pro-fibrotic cytokines such as TGF-β1, weakening the switch that drives scar formation. Together, these three actions gradually flatten a raised scar and fade its redness.

Dose, Interval, and Duration in Practice

Kenalog injection for a liposuction hypertrophic scar is delivered in very small amounts into the center of the elevation, in the mid to deep dermis. About 0.1 to 0.5 mL per lesion at 4 to 6 week intervals is a common regimen. Rather than aiming for a dramatic change in one session, staged flattening across multiple sessions reduces the risk of side effects. In most cases, clear softening and fading of redness are seen from the second or third session, and treatment ends after an average of 3 to 5 sessions. When response is limited, we consider combination therapy with laser or topical agents.

Side Effects and Risks You Should Know

The most common side effects are skin atrophy and telangiectasia. If injections are placed too deep, or if the concentration is too high, the scar can become depressed or the surrounding skin thins so that capillaries become visible. The next most common side effect is hypopigmentation (a vitiligo-like change), which tends to occur more in areas with denser melanin. Large or repeated doses can theoretically cause systemic effects such as menstrual irregularity or Cushingoid appearance, but these are rare at the small volumes used for liposuction port sites. Injection during pregnancy or lactation is avoided in principle. For safety standards in cosmetic surgery, please also refer to information from the Japan Society of Aesthetic Surgery.

Alternatives and Combination Therapies

Not every liposuction hypertrophic scar improves with Kenalog alone. As a first line, conservative treatment with silicone gel sheeting for at least 12 hours per day over 3 months is used. For cases with strong vascular dilation and redness, pulsed-dye laser (V-beam) is effective. For refractory cases, combined injection with 5-FU or scar revision with dermal suturing may be considered. At our clinic we assess the scar three months postoperatively and combine silicone gel, Kenalog, and laser to achieve improvement with the minimum possible invasiveness.

How AVAN TOKYO Applies This Protocol

At our clinic we check port sites and adhesion areas between the third and sixth postoperative month. If a hypertrophic scar tendency is observed, we first propose silicone gel sheeting as conservative care and introduce Kenalog injections only if the elevation does not subside. Excessive expectations and self-directed high-volume injections can cause skin atrophy, so it is essential that the treatment be planned and delivered under a physician’s supervision. For related postoperative topics, please also see our liposuction column archive.

Frequently Asked Questions

Q. Is a Kenalog injection painful?

It is usually mixed with a local anesthetic (lidocaine), so pain is reduced. However, scar tissue is firm, so pressure is felt more strongly than with an ordinary subcutaneous injection.

Q. How many sessions before I see results?

In most cases softening and fading of redness are visible from the second or third session, with an average total of 3 to 5 sessions. Individual variation depends on scar thickness and constitution.

Q. If side effects appear, will my skin return to normal?

Skin atrophy and telangiectasia often improve over several months to about a year, but they do not always fully reverse. That is why it is essential to use the lowest effective concentration.

Q. Can I receive the injection during pregnancy or breastfeeding?

Kenalog injections are avoided in principle during pregnancy and lactation. Even local administration is not completely without systemic influence, so please inform your physician of any possibility of pregnancy.

Q. Is this covered by insurance?

Insurance covers Kenalog for hypertrophic scars and keloids in general medicine, but when performed as management of the postoperative course of a cosmetic surgery it is usually handled within the self-pay framework.

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【Supervising Physician】Shin Moriwaki, MD (Supervisor)

Member, Japan Society of Aesthetic Surgery (JSAS) / Member, American Academy of Aesthetic Medicine

ECFMG Certificate (US Medical Licensing Qualification)

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