Triamcinolone acetonide intralesional injection for the treatment of keloid scars: patient selection and perspectives

Abstract

Keloids are pathological scars presenting as nodular lesions that extend beyond the area of injury. They do not spontaneously regress, often continuing to grow over time. The abnormal wound-healing process underlying keloid formation results from the lack of control mechanisms self-regulating cell proliferation and tissue repair. Keloids may lead to cosmetic disfigurement and functional impairment and affect the quality of life. Although several treatments were reported in the literature, no universally effective therapy was found to date. The most common approach is intralesional corticosteroid injection alone or in combination with other treatment modalities. Triamcinolone acetonide (TAC) is the most commonly used intralesional corticosteroid. The aim of this article was to review the use of TAC, alone or in combination, in the treatment of keloid scars. The response to corticosteroid injection alone is variable with 50–100% regression and a recurrence rate of 33% and 50% after 1 and 5 years, respectively. Compared to verapamil, TAC showed a faster and more effective response even though with a higher complication rate. TAC combined with verapamil was proved to be effective with statistically significant overall improvements of scars over time and long-term stable results. TAC and 5-fluorouracil (5-FU) intralesional injections were found to achieve comparable outcomes when administered alone, although 5-FU was more frequently associated with side effects. Conversely, the combination of 5-FU and TAC was more effective and showed fewer undesirable effects compared to TAC or 5-FU alone. Several kinds of laser treatments were reported to address keloids; however, laser therapy alone was burdened with a high recurrence rate. Better results were described by combining CO2, pulsed-dye or Nd: YAG lasers with TAC intralesional injections. Further options such as needle-less intraepidermal drug delivery are being explored, but more studies are needed to establish safety, feasibility and effectiveness of this approach.

Keloids: Current and emerging therapies

“…The incidence of keloids is highest among darker-pigmented persons of African, Asian and Hispanic descent and is estimated to be in the range of 5%–16%. 3 Males and females have an equal risk of developing keloids, 6 although incidence is slightly increased in females, likely attributable to them having more cosmetic procedures like ear piercing. 7 Persons aged 10–30 years are also at a higher risk of developing keloids.…”

“… 1 Various cytokines, growth factors and proteolytic enzymes have been implicated in the formation of keloids including transforming growth factor-β (TGF-β), epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), connective tissue growth factor (CTGF), tumour necrosis factor-α (TNF-α), insulin-like growth factor-1 (IGF-1), fibroblast growth factor-β (FGF-β), interleukin-6 (IL-6) and matrix metalloproteinases (MMPs). 3 , 14 , 18 Furthermore, signalling pathways such as Toll-like receptor signalling, SMAD signalling and fibronectin have been reported to be associated with keloid development. 18 , 19…”

“… 26 , 27 Intralesional TAC injections have been shown to reduce scar volume and height, improve scar pliability, and diminish associated scar pain and itching 8 as well as prevent recurrence. 3 Corticosteroids have anti-inflammatory and anti-mitotic properties. 1 Several other mechanisms have been reported by which corticosteroids reduce keloid scar including inhibition of fibroblast growth, attenuation of procollagen and glycosaminoglycan synthesis, reduction of endothelial budding and enhancement of collagen and fibroblast degeneration.…”

“… 34 TAC is used either alone as a monotherapy or in combination with other treatment modalities. 1 , 3 The response rates to corticosteroid injections vary clinically with regression rates in the range of 50%–100% reported after one year and recurrence rates in the range of 33%–50% reported after five years. 3 Combined therapy comprising surgical excision followed by TAC treatment also varied with reported recurrence rates in the range of 8%–50%.…”

“…2 The scar tissue extends beyond the original wound site and can be disfiguring and cause psychosocial issues impairing quality of life. 3 In addition, patients may present with symptoms such as burning, pain, pruritus, movement limitation and hyperaesthesia. 2…”