Abstract: Freckles are a hereditary disease that often occurs on the face and affects aesthetics. There are many freckle treatment methods, among which Q-modulated emerald laser and chemical peel are two relatively mature treatments. In this paper, we evaluated the clinical efficacy of these two treatment methods. The results showed that the cure rate of Q-modulated emerald laser was 84% and the cure rate of chemical peel was 57%, and the difference between the two groups was statistically significant (P<0.05).
Keywords: Q-modulated emerald laser; chemical peel; freckles.
Freckles, a pigmented hyperplastic skin disease with a genetic predisposition. It is commonly seen on the face and manifests as brownish punctate pigmentation spots, and sun exposure can promote and aggravate the disease. There are many freckle treatment methods, and 46 cases of freckles were treated with chemical peel method and Q-modulated emerald laser from 2009 to 2011 in our hospital, and the clinical efficacy is summarized as follows.
1. Clinical data
All 46 patients came from the dermatology clinic of our hospital and were randomly divided into two groups according to the order of consultation. In the experimental group, 25 patients were treated with Q-modulated emerald laser, 10 males and 15 females, aged 17-41 years old; in the control group, 21 patients were treated with chemical peel method, 9 males and 12 females, aged 17-38 years old. All patients were treated and clinically observed according to the treatment course.
2. Exclusion criteria
Exclusion criteria for the experimental group: ① keloid; ② those who could not adhere to postoperative light avoidance; ③ those with viral infections such as herpes simplex; ④ eczema patients, especially those with atopic dermatitis; ⑤ those with mental and emotional disorders, etc.
Exclusion criteria for the control group: ①pregnant and lactating; ②unable to insist on post-exfoliation light avoidance; ③localized surgical operation within six months; ④herpes simplex and other viral infections; ⑤immune insufficiency; ⑥received radiation treatment; ⑦localized chemical exfoliation within two weeks; ⑧scar body; ⑨eczema patients, especially atopic dermatitis; ⑩mental and emotional disorders, etc.
3.Treatment methods
3.1 Experimental group treatment methods
Take pictures before the operation, clean the patient’s skin make-up and oil, protect the eyes with wet gauze, and the operator wears protective glasses. The Q-switched alexandrite laser (produced by Sanosu) was used, with a wavelength of 755 nm, energy density of 6.5-7.5 J/cm2, frequency of 1-10 Hz, and a spot of 2-5 mm. The corresponding energy density, frequency and spot diameter were selected according to different skin tones, skin thickness and age. The laser handle is placed perpendicular to the treatment site, and the treatment can be seen at the time of rash graying or dotted epidermal peeling and burning sensation. After the procedure, the wound is iced for 20 minutes, and after the icing, a uniform application of gentamycin eye ointment is applied. 2 – 3 days later, a thin scab is formed on the wound, and the scab falls off after 1 – 2 weeks, avoid contact with water before the scab is formed, and pay attention to sun protection. The efficacy of the treatment was determined by follow-up examination after three months.
3.2 Control group treatment method
Pre-operative photographs were taken, analgesics were given half an hour before treatment, facial skin was cleansed with cleansing milk, facial oil was removed with 75% alcohol, and then spot removal solution (prepared with phenol, glycerin, 95% ethanol, camphor, dacronin hydrochloride, etc.) was applied to the skin surface of the whole face, starting from the hairline and eyebrows to prevent the drug from flowing into the eyes, mouth, lips, nostrils and hairs. After a few seconds or ten seconds or so, the skin becomes white. The skin starts to turn black after about half an hour, and the scab will be formed in about 5 days, and the scab will fall off naturally after 7 to 12 days.
4.Efficacy evaluation criteria and statistical methods
The improvement of facial skin was evaluated by physicians and patients. The total efficacy evaluation standard is 4 levels: healed is the lesion fading, and the normal skin is basically the same; effective is the lesion fading or fading 25% to 50%; ineffective is the lesion fading <25%, or there is pigmentation. Cure rate = number of cured cases/total number of cases x 100% [1].
The data were analyzed and processed using SPSSl0.0 statistical software. The efficacy of the two groups was compared by chi-square test, and P<0.05 was considered statistically significant.
5. Treatment results
Table 1 Comparison of the efficacy of the two methods for the treatment of freckles
Group
Number of cases
Cured
Effective
Effective
Ineffective
Cure rate
Experimental group
25
21
3
0
1
84%
Control group
21
12
2
1
6
57%
5.1 The treatment results of the two groups of freckle patients are shown in Table 1. 21 cases were cured in the laser treatment group, and the cure rate was 84% in the chemical peel treatment group. The difference in cure rate between the two groups was statistically significant (P<0.05).
5.2 One of the patients in the laser treatment group showed hyperpigmentation, the patient was pigmented and was advised to pay attention to sun protection, but no special treatment was given. In the chemical peel treatment group, 2 cases felt painful during the treatment, 2 cases had a slight heartbeat acceleration, 3 cases had redness and itching after treatment, and 6 cases had hyperpigmentation, all of which were given relevant symptomatic treatment.
6. Discussion
6.1 Freckle lesions are mostly aggravated in summer and reduced in winter, which is closely related to ultraviolet light. The pathology shows that freckle lesions are located in the basal layer of epidermis, and the melanocytes in the lesions are larger than those in normal skin, and their dendritic protrusions are longer and more numerous. UV light, an exogenous stimulus, significantly increases the ability of melanocytes to produce melanin and synthesize tyrosinase activity, resulting in rapid delivery of melanosomes to the stratum corneum [3]. Therefore, sun protection is necessary for freckle patients, and even lifelong sun protection is required.
6.2 The wavelength of Q-modulated emerald laser is 755 nm, which has highly selective photothermal effect and can selectively act on melanin particles in lesions, releasing high energy instantly to break them up, which are then engulfed by phagocytes or shed with scabs. At the same time, the laser pulse width is smaller than the thermal relaxation time of the target tissue, which will not cause thermal damage to the surrounding normal tissue. Usually one treatment can eliminate more than 80% of the lesions, with good effect and high safety; chemical peeling is to use the cytotoxicity of chemical drugs and protein coagulation to cause the destruction of epidermal cells, protein coagulation and dissolution, causing skin inflammation, and then use the process of wound repair to promote the division of epidermal cells, so that the collagen fiber arrangement is regular and homogeneous, so that the degenerated elastic dimension changes qualitatively. Reduce skin wrinkles, inhibit excessive sebum secretion, improve pore blockage, lighten pigmentation spots, and finally achieve the purpose of improving skin texture and cosmetic skin [4]. The treatment of freckles with phenol solution is one of them, which can achieve satisfactory results in removing spots, but its intraoperative and postoperative complications are more frequent, such as obvious pain during treatment, occasional cardiac arrhythmia or even fainting, and skin redness and oozing, itching, dryness and cracking, pigmentation and scar formation after treatment. Compared with Q-modulated laser, its safety factor is relatively lower. When comparing the two treatment techniques, Q-modulated alexandrite laser treatment is superior.
References
[1] Liao Leylan, Huang Guanghua et al. Clinical efficacy of intense pulsed light combined with Q-modulated laser for the treatment of freckles. Journal of Clinical Dermatology, 2011, 40(1): 56
[2] Tang J.-M. Laser cosmetic and dermatological therapeutics. Beijing: Military Medical Science Press, 2000, 128-129.
[3] Zhang Linxi, Wang Zhen, Guo Shuzhong et al. Effect of medium-wave ultraviolet light on human melanocytes cultured in vitro. Chinese aesthetic medicine, 2001, 10(3): 180-182.
[4] Jin L, Wang P. Chemical peeling and its application in dermatology. Chinese Journal of Integrative Dermatology and Venereology, 004, 3(1): 57.