Treatment of hypertrophic scars and keloids is challenging because of the potential of recurrence in these scars. Therapies are thus based on combination approaches with the goal of preventing reformation of keloids and hypertrophic scars after treatments. Treatment initiation is recommended when the scar is immature, and the overlying epithelium is intact.
Hypertrophic scars are of different morphological types. These are:
A – Erythematous or Immature scars
B – Linear hypertrophic scars
C – Widespread burn scars
D – Minor Keloids
E – Major Keloids
Topical silicone gel reduces scar thickness, improves color, and prevents formation of keloids in high-risk patients. The most probable mechanism of action with silicone has been suggested to be hydration and occlusion. Pure silicone products are available in a variety of formulations including gel sheets, self-adhesive silicone gel dressings and silicone oil. Recent research has led to the development of a new silicone gel that can be applied on surgical wounds immediately after surgery or open wounds following chemical peels and lasers. Applying silicone gels at the time of surgery or after a procedure may prevent formation of hypertrophic scars and keloids. Silicone oil with a stabilized hypochlorous acid is a newer formulation that can modulate wound healing. Silicone gel sheeting also provides symptomatic relief in scar redness, itchiness and tenderness. Silicone gel sheeting is easy to use and may be especially useful in children who cannot tolerate the pain of other procedures.
Compression may facilitate scar healing by decreasing blood flow and oedema and increasing collagen breakdown. Compression therapy is a standard care for prevention and treatment of hypertrophic scars from burns. High pressure therapy is more effective compared to low pressure therapy. Pressure on scars is maintained by a variety of devices such as fitted garments, elastic adhesive bandages, button compression, common wraps and pressure earrings (for ear lobe keloids). Elastomer inserts with thermoplastic backing have also been used to decrease facial hypertrophic scar formation. Custom-made pressure clips may be used for 12 hours a day for 6 to 18 months following ear lobe keloid treatments. It is generally recommended that pressure should be maintained between 24–30 mm Hg for 6 –12 months for this therapy to be effective. Long-term compliance is a significant issue with this therapy. Compression therapy is especially found beneficial in the treatment of burn scars in children.
Intralesional corticosteroids are first line therapy for keloids and second-line therapy for hypertrophic scars. Intralesional corticosteroids can be used alone or in conjunction with other treatments. Intralesional triamcinolone (TAC) can be administered into the papillary dermis at a concentration of 10 to 40 mg/mL, over an interval of 4 to 6 weeks till the scar has flattened. They play a crucial role in providing symptomatic relief in pain and pruritis. Low doses may help minimize side effects including dermal atrophy, telangiectasia, and hypopigmentation. Intralesional steroid injections are administered after surgical excision of ear lobe keloids and hypertrophic scars to prevent recurrence. When corticosteroids are injected at the time of surgery there is a significant risk of wound dehiscence. However, triamcinolone (40 mg/ml) layered into the wound without injecting into the tissues appears to be safe and efficacious. Intralesional corticosteroid injection is associated with significant injection pain therefore, so compliance from patients may be poor. Care must be taken to avoid adverse events which can include telangiectasia formation, skin or fat atrophy, and hyperpigmentation or hypopigmentation. Topical corticosteroid creams have also been tried with varying success
Surgical removal of keloids can be a full excision with primary closure or shave excision left to heal by secondary intention. Surgical excision alone has a high recurrence rate in keloids and hypertrophic scars. Surgery is the first line treatment for disabling scar contractures. Different techniques like Z plasty, W plasty, grafts and skin flaps may be used.
Cryosurgery uses a refrigerant such as liquid nitrogen that causes tissue necrosis and flattening of the keloidal tissue. It can be administered intralesional or as contact spray. Repeated monthly sessions are required. Because melanocytes are sensitive to cold temperatures, this treatment often results in significant hypopigmentation. Intralesional cryotherapy performed through a 20 G injection needle or an intralesional cryoprobe is able to concentrate the cold temperature within the lesion and prevents external epidermal damage. Cryotherapy is effective in improving scar hardness, elevation, redness, itching and pain. Cryotherapy facilitates penetration of corticosteroid injections and is regularly combined with intralesional TAC to augment therapeutic efficacy.
The use of radiation therapy has been found to be a novel, yet game-changing procedure for many patients with keloids who have lesions that may have, in the past, been difficult to treat and in those lesions where high recurrence rates were expected. Radiation therapy acts by inhibiting angiogenesis and prevention of fibroblast repopulation after surgical excision of lesions. Radiation therapy can be administered as both external beam therapy, and brachytherapy. External beam radiation typically requires higher dose due to increased distance between the source of radiation and the scar, while brachytherapy (internal radiation) is more targeted as it is incorporated into the lesion. Radiation therapy is not recommended for pregnant patients, patients less than 12 years of age, or for treatment of keloids in radiosensitive locations (such as the thyroid). One concern for radiation treatment is the development of radiation-induced malignancy years after treatment.
Superficial radiation therapy (SRT) is a US FDA approved procedure for the treatment of keloids and results to date have shown that when performed following a surgical procedure, recurrence rates at one year are under 10%. SRT can be performed in one’s clinical office. SRT may be performed for three consecutive days post keloid excision. The radiation dose is calculated and delivered in three doses, or fractions, so as to limit the potential for any adverse effects, or radiation dermatitis that may be seen when giving large doses of radiation.
Interferons are cytokines with antiproliferative and antifibrotic effects. Interferons interfere with collagen synthesis and fibroblast proliferation, potentially by modulating TGF-b. Interferon alpha-2b can be administered thrice weekly as adjuvant therapy post excision. Interferon gamma may be administered intralesional once weekly for up to 10 weeks. Interferon injections are reported to be significantly better than triamcinolone acetonide injections in preventing post-surgical recurrence of keloids
5-Fluorouracil (5-FU) is an antimetabolite and has a role in treating keloids and hypertrophic scars. 5FU inhibits fibroblast proliferation and TGF-b–induced expression of Type I collagen. Intralesional 5-FU has been studied as monotherapy, in conjunction with intralesional TAC, or as adjuvant therapy post excision. Common side effects include pain at injection site, ulceration, burning sensation, and hyperpigmentation. Injection 5 FU 50mg /ml can be administered alone or with TAC at 2-4 weekly intervals 5FU in combination with intralesional TAC has better efficacy than triamcinolone or surgical excision alone. Combination of TAC (40mg/ml) and 5 FU (50mg/ml) can be prepared in the ratio 1:3 and administered intralesionally once in 2-3 weeks. This drug is not recommended during pregnancy and in patients with bone marrow suppression.
Imiquimod is a topically applied immunomodulator that induces expression of apoptotic genes in keloidal tissue. Imiquimod 5% cream applied alternate night for 2 months after surgery has been studied for its potential use as adjuvant therapy after surgical removal of keloids. Main adverse reactions reported include hyperpigmentation, irritation, erosion, and pain.
Tacrolimus is an immunosuppressant with multiple potential therapeutic targets in the treatment of keloids. It has been shown in vitro to block TGF-b/Smad signaling pathway leading to reduced fibroblast proliferation, migration, and collagen production.
Bleomycin is a cytotoxic antibiotic with antineoplastic properties. Intralesional injections of bleomycin 0.1ml (1.5 IU/ml) at a max dose of 6 mL, 2–6 sessions within a month have shown improvement in keloids and hypertrophic scars.
Verapamil is a calcium channel blocker that inhibits inhibiting influx of calcium into the cell. Verapamil has been shown to increase synthesis of procollagenase causing reduced production of fibrous tissue. Intralesional verapamil (2.5mg/ml) is used as monotherapy or as adjuvant therapy after excision of lesions with or without silicone.
Onion extract creams have been a subject of active clinical interest. Onion extract contains flavonoids (quercetin and kaempferol) that play a role in reducing scar formation through inhibition of fibroblast proliferation. Quercetin also has anti-inflammatory properties.
Tension is implicated in the pathogenesis of keloids, and the use of botulinum toxin is thought to reduce tension on the wound by preventing underlying muscle contraction during the healing phase. Botulinum toxin type A (BTXA) inhibits the exocytosis of acetylcholine, thereby blocking neuromuscular activation, leading to muscle flaccidity. Recently, intralesional injection with BTXA was also proposed for the treatment of established keloids. BTXA injected into lesions at 3-month intervals for a maximum of 9 months resulted in scar regression at 1 year follow up. However, the suggested clinical efficacy of intralesional BTX A for the treatment of keloids is uncertain and requires more in-depth studies, which are ongoing at this time.
One of the more fascinating treatment options which has become more routine amongst physicians is the use of lasers in treating hypertrophic scars and keloids. The Pulsed Dye Laser (585 nm) was the first used and preferred laser for both hypertrophic scars and keloids and showed promise in elimination of erythema and flattening of hypertrophic scars.
Recently, ablative fractional lasers (10600nm CO2 and 2940 nm Erbium Yag) have shown better outcomes in postoperative treatment of surgical scars versus pulsed-dye laser alone. Ablative fractional lasers reach greater depths than pulsed dye lasers and require fewer sessions for optimum results. Through the development of heat-shock proteins, one can use the fractional capabilities of the CO2 laser to interact with the scarred collagen and help to develop new collagen in its place. Common side effects after fractional laser treatment include transient erythema, edema, and purpura. Ablative fractional laser along with triamcinolone acetonide delivered topically may provide an efficient, safe, and effective therapy in improving pigmentation, vascularity, pliability, and scar height in hypertrophic scars. With the use of lasers, it is now understood that early initiation of treatment of hypertrophic scars gives better results.
Initial & secondary management of hypertrophic scars & keloids based on morphological type
If erythema persists for more than one month, the risk of hypertrophy increases and management should be as for a linear or widespread hypertrophic scar
Pulsed Dye Laser sessions
Silicone gel sheeting or gel should be used as first line therapy. If the scar is severe, itchy or resistant to silicone therapy further management with corticosteroid injections should be started. Triamcinolone injections are administered in the dose of 2.5-20 mg/ml over face and neck and 40mg/ml over lesions on trunk.
If silicone gel sheeting or gel, pressure garments, and intralesional steroid injections are not successful after 12 months of therapy then surgical excision with concurrent use of silicone gel sheeting should be considered. An option for more severe scars is reexcision with layering of triamcinolone acetonide. Specific wavelength laser therapy and cryotherapy can also be instituted. Superficial Radiation Therapy also works well in these cases.
The treatment of burn scars often requires a combination of techniques including individualized pressure therapy with customized garments, massage, silicone gel sheeting, use of corticosteroids, and surgical procedures such as Z-plasty, excision and grafting or flap coverage. For wide scars some improvement may be possible with surgery but may require serial excisions or preoperative tissue expansion. A variety of other adjunctive therapies such as hydrocolloids and antihistamines to relieve itching are used. Pulsed dye laser therapy may be of value.
First-line therapy for most minor keloids is a combination of silicone gel sheeting and intralesional corticosteroids. Localized pressure therapy such as ear-clips on earlobe keloids and compression garments are commonly used
If silicone gel and intralesional corticosteroids are unsuccessful, surgical excision within the boundaries of the keloid should be considered. If all other therapies are unsuccessful, specific wavelength laser therapy could be considered. For earlobe keloids surgical excision can be recommended as first-line therapy followed by combination therapy of steroid injection and silicone gel sheeting. Excision of keloids with grafting of skin taken from the excised keloid followed by immediate radiation therapy can be tried, but the long-term risks of radiation must be carefully weighed
A trial of silicone gel sheeting or gel and corticosteroid injections may be worthwhile, but these scars may require surgical excision and specialized management
If first-line therapy with silicone gel sheeting or gel, pressure therapy and intralesional corticosteroids is not successful, specific wavelength lasers and then surgical excision are indicated. Extensive counselling with the patient is required before embarking on a surgical solution because the recurrence rate is high. For some patients, symptomatic treatment with antihistamines may be all that is possible. Ongoing patient counselling and advice on prevention are essential components of this therapy.
Subcision combined with microneedling or fractional lasers
Subcision followed by soft tissue augmentation with fillers or autologous fat