S2k guidelines for the therapy of pathological scars (hypertrophic scars and keloids) – Update 2020

Abstract

This S2k guideline is an update of the German guideline published in 2012. Some of the passages were taken from the previous version [1]. This is the short version of the guideline. The long version can be accessed at www.awmf.org. It contains additional information e.g. on the expert committee, on use, scope and objectives, on financing, implementation and dissemination as well as management of conflicts of interest, a clinical introduction, and case reports. The terms and symbols listed in Table 1 were used to offer standardized recommendations. Hypertrophic scars and keloids are basically benign skin lesions. Any need for treatment is determined by the symptoms (e.g. pruritus/pain), by functional impairment (e.g. contraction/mechanical irritation due to elevation) or can be rationalized on aesthetic/cosmetic grounds, when a significant impact on quality of life and stigmatization can be foreseen [2]. Bock et al. developed an instrument to assess quality of life specifically for patients with hypertrophic scars and keloids. In their validation study, a severe impairment of quality of life was observed [3]. Therapeutic goals must be set on an individual basis; the main consideration is to alleviate the patient’s complaints. Depending on the method chosen, a clear improvement (e.g. volume reduction by 30–50 %, decrease of symptoms > 50 %, and/or sufficient patient satisfaction) should be achieved after 3–6 treatment sessions or after 3–6 months of therapy. None of the currently available methods for scar therapy can guarantee scar reduction or an improvement of the functional and/or cosmetic situation in all cases. The treatment method of first choice cannot be standardized for scars, as too many variables influence their development and regression (e.g. location, age and type of the scar, genetic predisposition). A combination of various treatment methods is often required to achieve success. The main methods for documentation in day-to-day practice include documentation of size and thickness and photographs. Patient satisfaction and reduction of symptoms are further important considerations. Clinical studies currently use scales such as the Vancouver Scar Scale (VSS), Patient and Observer Scar Assessment Scale (POSAS), Visual Analog Scale (VAS), two-dimensional keloid modeling as well as mid- to high resolution B-image sonography. Subjective assessment scales are, however, of only limited use for large scars or for evaluating functional impact [4-6]. 3D imaging is also used, in particular for clinical studies. Algorithms for treating hypertrophic scars and keloids are depicted in Figures 1-3. Glucocorticoids (aka glucocorticosteroids) reduce excessive scar growth by decreasing the synthesis of collagen and glycosaminoglycans, and inhibiting fibroblast proliferation. In addition to the known anti-inflammatory effect of glucocorticoids, they also inhibit iNOS transcription (iNOS, inducible form of NO synthase [7]) thus reducing collagen production in fibroblasts and inhibiting synthesis of alpha-2-macroglobulin, a collagenase inhibitor. The injections are painful. If the injection is too deep, atrophy of the subcutis may develop; if the injection is too superficial, telangiectasias and disturbed pigmentation may ensue. Whitish deposits of the crystal suspension may also occur. Most commonly, triamcinolone acetonide (TAC) is used at a dose of 10–40 mg, at most 5 mg/cm2. It can be injected as is, or diluted 1 : 2 to 1 : 4 with either NaCl 0.9 % or lidocaine. The injection must be administered in a strictly intralesional manner with a syringe that should ideally have a locking needle (Luer system). Blanching of the injected tissue indicates that infiltration is complete. Repeat injections may be administered at three to four week intervals if required. One study showed that starting with a low concentration of triamcinolone (10 mg/ml) and increasing it over time (to 20 mg/ml resp. 40 mg/ml) may reduce the risk of possible side effects and the relapse rate [8]. Superficial spray cryosurgery immediately prior to the intralesional glucocorticoid injection causes edema and facilitates infiltration [9]; it also reduces pain. As a preventative measure, injection of 1 mg triamcinolone per centimeter directly into the wound margins during surgery has shown good efficacy without topical side effects [10]. Treatment success is most likely if active scars – i.e. bright red, or subjectively symptomatic (pruritic or painful) – are treated with TAC. This is based on the mechanism of action. If there is no improvement after three therapy sessions with triamcinolone, the treatment regimen should be adapted, for example by combining it with 5-fluorouracil. Efficacy of triamcinolone acetonide in keloid treatment: a systematic review and meta-analysis. Wong TS et al. Front Med (Lausanne) 2016; 3: 71. The effect is based mainly on changes in microcirculation with cold-induced alteration, thrombosis and consecutive ischemic cell death. Protracted healing time of about four weeks and frequent (reversible) depigmentation due to destruction of cold-sensitive melanocytes. In most cases, repeat procedures at intervals of 4–6 weeks are required until the scar has been sufficiently flattened. Due to its various limitations, intralesional cryosurgery is only infrequently used. The required needle is a single-use medical product; its cost presents a significant hurdle for the procedure, particularly on an out-patient basis. Depending on the size of the keloid, several needles may be required, and treatment of larger keloids is time-consuming. Under sterile conditions, nitrogen is instilled into the keloid via a double hollow needle after local anesthesia. The whole keloid is then frozen, with a halo of 3–5 mm around the lesion. Resolution of the keloid occurs within approximately four to six months (35). The patient should be advised to expect a blister progressing to a weeping wound; antiseptic treatment may be indicated. The next treatment session should take place only after healing of the defect caused by the previous treatment. Dark-skinned patients must also be warned of possible hyperpigmentation or hypopigmentation. Active keloids may worsen after spray cryosurgery, and in these cases, a combination e.g. with subsequent triamcinolone injections is helpful. Efficacy and safety of triamcinolone acetonide alone and in combination with 5-fluorouracil for treating hypertrophic scars and keloids: a systematic review and meta-analysis. Ren Y et al. Int Wound J 2017; 14(3): 480–7 Intralesional cryotherapy for the treatment of keloid scars: evaluating effectiveness. van Leeuwen MC et al. Plast Reconstr Surg Glob Open 2015; 3(6): e437 Localized pressure reduces capillary perfusion; it accelerates maturation of collagen and thereby flattens the scar. Unpleasant sensations due to heat, sweating and swelling of the limbs, dermatitis, pressure erosions and ulcerations. Pressure therapy, usually with elastic materials, should be started as early as possible (i.e. upon conclusion of re-epithelialization), or even preventively in patients with a predisposition for the development of pathological scars. The required pressure is 20–30 mmHg (corresponding to compression class II) and should be maintained over the whole day, i.e. 24 hours. Pressure therapy is usually performed with pressure suits or bandages, sometimes with transparent plastic masks or pressure buttons in special locations. With compression bandages made of the preferred long-stretch material, slight differences in circumference (e.g. edema) have less of an impact than with short-stretch material, so that the still tolerable maximum pressure is reached distinctly later, while on the other hand the still effective minimum pressure is less likely to be missed. With individually made pressure bandages, the applied pressure declines after about six months due to the properties of the material. Pressures may be slowly reduced over the course of the treatment period of 6–24 months. In postoperative prophylaxis, the treatment period should last at least 6–24 months. This treatment requires a lot of effort from the patient, and adherence is demanding for both patients and physicians. Treatment is sometimes expensive, so the initial findings and changes over time should be documented carefully. The effects of conservative treatments on burn scars: A systematic review. Anthonissen M et al. Burns 2016; 42(3): 508–18 Hypertrophic scars and keloids are fibroproliferative skin diseases of varying duration and intensity of inflammation. They are caused by genetic, systemic, and topical risk factors. The type of damage to the reticular dermis, such as thermal damage and impaired healing with prolonged inflammation, may result in disrupted scarring. Mechanical tension plays a major role in this process. This offers an opportunity for surgical prevention and intervention, since genetic and systemic causes cannot currently be influenced. Surgical treatment itself carries a high risk of recurrence, especially in case of keloids, resulting in lesions that are often larger than the original lesion. An indication for surgery should therefore be declared with caution, except in cases of small hypertrophic scars. In addition, the normal risks of skin surgery need to be considered. Undisturbed wound healing and avoidance of mechanical tension are important particularly in patients with a history of keloid formation. Measures to achieve this include: atraumatic surgical techniques, multilayer suturing techniques that avoid tension, use of materials suitable for the location, use of zig-zag plasty (W, Z) in incisions crossing joints, and flap surgery in case of excisions to relieve tension. The indication for surgery must be carefully verified. Optimal post-operative care with the aim of rapid healing reduces the risk for keloids resulting from a prolonged inflammatory phase. Epidermal wound healing requires 7–10 days, but this is insufficient for dermal healing and stabilization of the scar. Since the healing dermis reaches 90 % of its former stability only after three months, a reduction of mechanical tension through rest, butterfly bandages, silicone sheeting or compression is recommended over a longer period. Revision surgery for hypertrophic scars usually yields satisfactory results, but the recurrence rate for keloids is 45–100 % if only surgery is employed. Any kind of plastic surgery may be used – from primary wound closure to flap techniques, if the timing is considered for hypertrophic scars and surgery is combined with an effective adjuvant treatment for keloids, especially in case of recurrence. Z-plasty is suitable for relieving linear contractures and tension over joints. Long, longitudinal scar tracts are converted into shorter sections within the relaxed skin tension lines (RSTL) and extended depending on the angles. This reduces mechanically induced inflammation. In addition, shorter scar sections mature more rapidly. W-plasty is suitable for flat areas on the face but not over expression lines or joints. Scars should be excised completely. Scar tissue in the flap tips will increase the risk of necrosis. As opposed to scars, healthy skin can stretch and relieve tension. Skin grafts are suitable for replacing large areas of scarred skin, but they are themselves prone to developing secondary contractures. Very thin “isotopic” split skin grafts, harvested in the area of the scar before excision of the dermal scars and subsequently re-positioned in loco, may be used for extensive hypertrophic scars. There is a recent description of this technique for scars after self-injury [11]. Flap surgery is superior for relieving scar contractures since – as opposed to grafts – flaps have a natural tendency to relax. Apart from local flap surgery, other techniques include pedicled flaps, free flaps, distant flaps and expanders. Flap surgery is also required for reconstruction of large defects after resection of extensive keloids which are themselves usually recurrences after previous surgery. Any keloid risk at the donor site should be minimized by using highly effective adjuvant treatments such as postoperative radiation therapy (see the relevant chapter below). Dermal suturing is unable to achieve tension relief in the reticular dermis, though this is important for preventing recurrence. For this purpose, fascial sutures can be added for the trunk after block-like deep resection of the subcutaneous tissue down to the muscles, and broad subfascial mobilization [12-14]. In view of genetic alterations and local recurrence after excision, keloids may be said to show neoplastic properties. They have an inactive center and a progressive and in part even infiltrative margin. This suggests that extramarginal excision is more prudent than intramarginal excision. Recent studies have also shown that histologically incomplete excision results in increased recurrence rates [15, 16]. Long-term care and instruction of the patient are essential for achieving lasting success after surgery. Healing disorders, e.g. due to radiation, must be treated. Timely immobilization, pressure/compression and butterfly bandages may assist in tension relief. Conservative treatment (see the respective chapters) can supplement recurrence prophylaxis. Lipotransfer and treatment with fatty tissue-derived mesenchymal stem cells are still at an experimental stage. It is hoped that these will have anti-inflammatory and anti-fibrotic effects; this is to be systematically addressed in preclinical studies [17]. Keloid excision and adjuvant treatments. A network meta-analysis. Sitios C et al. Ann Plast Surg 2019; 83: 154–62 Ablative lasers (CO2, Er:YAG, Er:YSGG and thulium lasers) can be employed either in circumscribed areas, or in a fractional manner. The latter method leaves some vital tissue between the ablation zones, ensuring specific efficacy with a low rate of side effects. A specific sequence of spatiotemporal wound healing, involving heat shock proteins from the epidermis the ablation to and dermal This results in of and tissue and even the these lasers are used to scars, in addition to scar and pigmentation often This can for in the improvement of the functional of contractures. Ablative treatment causes and at high can also and and hyperpigmentation are usually more and more after since lasers or are also possible is directly after or as early as Treatment of at least six sessions at intervals are to be This is by the to either the treatment or to further in the scar tissue may also be to treatment is and can be performed rapidly. alone or combined with with the method usually results in the improvement of or more of the scar or as well as in an improvement of the cosmetic Treatment of keloid scars using and a review of the et al. Med 2017; treatment reduces resulting in and and regression of pathological scars. There have also been of reduced expression of and fibroblast of of fibroblast and of and after use of A often that can then for to Depending on the by the and on the patient’s skin and may also occur. hyperpigmentation is more frequent in with a skin type but is more at a of than at Depending on the patient’s skin treatment with a is usually performed with an of approximately and a of or about with of least treatment sessions at an of about six to weeks are to the deep dermal results in a reduction of fibroblast collagen this treatment is also painful. Treatment treatment are to be The mechanism of is the as for lasers with a there is a of in case of excessive damage for skin and Treatment standardized and on the used. treatment sessions at intervals using show the and most Treatment of keloid scars using and a review of the et al. Med 2017; In the skin is with many small The resulting a wound healing that to skin There is a risk of or dermatitis, and of developing There have been of after as well as of the of hypertrophic scars in a is with needles of to mm can be to a or a and are applied to the Treatment is usually performed after of a local or even in the case of extensive lesions. 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An dose of is recommended in three to four or a This should be performed within week after surgery. postoperative radiation therapy may to and in the area of the scar, lasting for about side effects after radiation therapy include hyperpigmentation and skin, and these are observed after of 20 using with an dose of effects on the skin are In no study has a been between of keloid scars and secondary Keloid excision with subsequent offers the recurrence rates (10 % on of radiation therapy show recurrence there is a of studies on this adjuvant radiation therapy result in rates of keloid recurrence than techniques offers the recurrence rates % by % and radiation therapy % It is recommended that the time between keloid excision and be as short as There is a in keloid recurrence rates after postoperative depending on radiation was started within within 24 or after 24 hours. In studies radiation therapy was within recurrence rates of only % were observed Treatment should be performed in with an of plastic surgery, radiation keloid excision and adjuvant radiation therapy, the postoperative procedures and special for wound care should be as with other methods for keloid for keloids: a systematic review recurrence rates between radiation et al. of plastic surgery 2017; Surgical with for Treatment of Keloid A van Leeuwen MC et al. Plast Reconstr Surg Glob Open 2015; 3: in The mechanism of for silicone has not been and the resulting increased particularly of the is to a effect on fibroblasts via from 24 weeks of silicone reduced of cells and a reduction in the increased expression of from intralesional fibroblasts were observed may result in in cases. are available as and use is over a period of to 24 If they are used preventively after surgery, treatment may after treating use should be until the wound has been Treatment usually for several weeks to months. for the of silicone for preventing hypertrophic scars and keloids is There are some for a in the treatment of hypertrophic scars and keloids in terms of scar thickness and sheeting for preventing and treating hypertrophic and keloid scars. et al. of silicone sheeting and silicone for the prevention of hypertrophic scars and keloids. et al. 2017; has anti-inflammatory and effects and fibroblast proliferation. of 1 and of the have been as possible of of the can to In an should be several a day, and ideally with into the scar For scars, after may be considered. If used preventively after surgery, treatment may after the sutures have been treating use should be until the wound has been Treatment usually for several weeks to months. with other as may irritation and should be used with caution, particularly on the face or in small on the of for the prevention or treatment of hypertrophic scars and keloids are not the from clinical studies is The 5-fluorouracil fibroblast proliferation. on skin ulcerations. is usually four weeks at a concentration of 50 mg/ml and a maximum dose of mg per treatment As with is injected strictly with a syringe that ideally has a locking studies in recent have shown that a combination of and either at a : 1 or : 1 to be superior to either as This is an and the patient must be Treatment with good especially when combined with other side effects are less than with triamcinolone, and so it can be used in areas In some is used of particularly in of is in As with the risk of skin in patients is said to be with The is injected directly into the scar tissue at a concentration of is for treating hypertrophic scars and keloids, which a for primary Efficacy and safety of triamcinolone acetonide alone and in combination with 5-fluorouracil for treating hypertrophic scars and keloids: a systematic review and meta-analysis. Ren Y et al. Int Wound J 2017; 14(3): 480–7 long version of this guideline at www.awmf.org.

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