Scars are the permanent remaining sign of deeper injuries of the skin and are formed in the course of physiological wound healing. While people generally come to terms with physiological scars, the level of suffering and the therapeutic challenge is very high in the case of pathological scars. The prevention and treatment of these so-called hypertrophic scars and keloids remains a therapeutic challenge for the treating physician.
Basically, keloids belong to chronic skin diseases, which are benign skin lesions. The need for treatment results from the symptoms, such as itching or pain, or from functional impairments, such as contraction or mechanical irritation due to elevation, as well as from aesthetic and cosmetic reasons, some of which can lead to a high restriction of the quality of life with stigmatization [1,2].
The therapy goals are to be determined individually and should be based primarily on the patient’s complaints. The treatment method of first choice cannot be standardized for scars because too many variables influence the development and regression of scars, such as localization, age and type of scar, or genetic disposition. Often a combination of different treatment methods is required. However, depending on the treatment option chosen, a significant improvement should be achieved after three to six treatments or after three to six months of therapy, i.e. a volume reduction of 30-50%, a symptom reduction of >50% or sufficient satisfaction on the part of the patient.
Current therapy options according to S2k guideline
The search for therapeutic options continues unabated. As a result of increasing clinical experience and building on published evidence, an update of the S2k guidelines for the treatment of hypertrophic scars and keloids was made [3]. Standard therapy recommended includes strictly intralesional injection of glucocorticosteroids, e.g., injection of triamcinolone acetonide 10 to 40 mg/ml, maximum 5 mg/cm². A blanching effect of the injected tissue indicates the end point of infiltration. Additional injections may be given at approximately three to four week intervals as needed. In the case of hypertrophic scars as well as keloids, a combination with cryosurgery is also recommended. Cryosurgery can be performed either as a spray and contact procedure or as intralesional cryosurgery. Repetition at four to six week intervals is usually required.
Another option is pressure treatment, which is used especially for hypertrophic scars after burns or scalds. Treatment is usually with compression suits or bandages, sometimes with transparent plastic masks or press studs in special localizations. The required pressure is 20 to 30 mmHg, corresponding to compression class II, and should be maintained all day. For postoperative prophylaxis, the treatment period should be at least 6 to 24 months.
Surgical treatments are recommended only in separate situations because of the high risk of recurrence with the potential for aggravation. In the case of traction-triggered scar growth, for example, surgical traction reduction can be performed. Excision can also be useful if small hypertrophic and cosmetically disturbing scars have developed as a result of impaired wound healing. Even with very large, bulky keloids, in some cases there is no alternative to surgery.
Radiation as a follow-up treatment after surgical therapy is characterized by good evidence. Thus, adjuvant radiotherapy is recommended after keloid excision for large keloids and for keloids that are difficult to treat with other methods. The best results of postoperative irradiation are achieved within seven hours. In contrast, primary monotherapy of hypertrophic scars and keloids by irradiation is not recommended.
Treatment with 5-fluorouracil (5-FU) also shows good response rates, especially in combination with other therapeutic options. Classical use is once a week at a concentration of 50 mg/ml and a total dose of maximum 50 to 150 mg per treatment. Analogous to TAC, 5-FU is co-injected strictly intralesionally into the scar tissue using a syringe ideally with a tightenable needle. Over the past several years, various studies have shown that the combination of 5-FU with TAC appears to be superior to either 9:1 or 3:1 monotherapy.
In laser therapy, ablative fractional lasers are used in addition to the dye laser. While the former lead to hypoxemia in scar tissue with subsequent reduction of fibroblast activity in still fresh, reddened scars via absorption in hemoglobin, the use of fractionated lasers also induces remodeling processes in scar tissue in later stages of scar maturation, which can be proven histologically.
Also included for the first time was mironeedling, in which the skin is pierced with many small needles to trigger a wound healing cascade that is said to lead to remodeling in the skin. Microneedling alone or in combination with “needling-assisted-drug-delivery” is particularly recommended for the treatment of hypertrophic scars, especially hypertrophic scars after burns or scalds. On the other hand, the treatment of keloids by microneedling is not recommended.
Preparations with silicone and Extractum cepae are listed as another therapeutic option. For postoperative prophylaxis of de novo development of hypertrophic scars and keloids and for recurrence prophylaxis, the guideline recommends the use of combination preparations with Extractum cepae and silicone preparations.
Retrospective, monocentric analysis yields new results
A study summarized in the DDG abstract volume examined the success of different therapies in a retrospective analysis. For this purpose, extensively available image material was evaluated in a before/after comparison by three independent experts. The study included 141 patients with keloids treated between 2005 and 2019. The evaluation showed a balanced proportion of women and men, and over 90% of patients were of Caucasian origin. Especially for keloids in the area of the ears, the topical application of Imiquimod after excision resulted in a good therapeutic success. Without excision, consistent compression therapy with customized bandages or girdles yielded good regression of size and also of symptoms. At other sites, excision has been combined with brachytherapy or sequential intralesional injections with triamcinolone acetonide crystal suspension have been used with less good success rates. Keloids after acne and with sternal localization proved to be particularly refractory to therapy. The best results were achieved with keloids in the ear area and after excisions of e.g. nevi. The data show that the treatment of keloids is still a major challenge today and is judged to be unsatisfactory overall. Therefore, the development of new therapies is urgently needed [4].
Literature:
- Balci, et al: DLQI scores in patients with keloids and hypertrophic scars: a prospective case control study. J Dtsch Dermatol Ges 2009, doi: 10.1111/j.1610-0387.2009.07034.x.
- Bock, et al: Quality of life of patients with keloid and hypertrophic scarring. Arch Dermatol Res 2006, doi: 10.1007/s00403-006-0651-7.
- Nast, et al: S2k-Leitlinie Therapie pathologischer Narben (hypertrophic scars and keloids) – Update 2020. J Dtsch Dermatol Ges 2021, https://doi.org/10.1111/ddg.14279
- Jeschke, et al: Therapy of keloids: Results of a retrospective, monocentric analysis. Journal of the German Dermatological Society (JDDG), Volume 19, Supplement 2, February 2021.
HAUSARZT PRAXIS 2021; 16(10): 44-45
