Vol. 15 •Issue 4
• Page 45
Lasers, Peels, Injections And Masks
An Overview of Treatment Modalities for Scars
By Christine M. Erdmann, NP
Scars are abnormal formations of connective tissue that suggest dermal damage.1 Scarring occurs when fibroblasts deposit gristle-like fibers to breaks in the skin and hold the wound closed, leading to a distorted appearance.2 Scars can result after acne, surgery, burns, scratches, cuts and other trauma.
Keloid and Hypertrophic Scars
Keloid and hypertrophic scars occur after cutaneous injury and consist of exuberant fibrous repair tissues. A hypertrophic scar stays confined to the original site of injury, whereas a keloid expands beyond the original injury site, often with clawlike extensions.3
Hypertrophic scars occur in people who are genetically inclined to them. They result from skin trauma and are formed by excessive collagen deposition during wound healing. They are occasionally pruritic but typically asymptomatic. Common sites for hypertrophic scars are on the deltoid, upper lip, sternum and mandible. They may involute spontaneously within 6 to 18 months.1
Keloids develop spontaneously or 3 to 5 weeks after skin trauma. They start as firm, rubbery masses with telangiectasia and a pink to red hue. In time, they extend outside the traumatized spot and become irregularly shaped and hyperpigmented. Patients often complain of associated tenderness and pruritis. Common areas of involvement include the earlobes, face, neck, chest, abdomen and upper back.1 African-Americans and Asians have an increased genetic predisposition to keloid formation.
Treatment Options
Triamcinolone acetonide (Kenalog), also known as TAC, is a steroid that is injected intralesionally into a hypertrophic mass to flatten and shrink the scar. The typical dosage is 10 mg/mL to 40 mg/mL, and the injections are given every 4 weeks until the mass has flattened to match normal skin level. The dosage and the number of injections vary based on the size of the keloid and how the scar reacts to treatment.
TAC is fast acting, and many patients report visible flattening within 3 hours of injection. Although the steroid can help flatten the scar, it does not seem to decrease its red or hyperpigmented color. However, in patients with darker skin, the lesion and surrounding area may become hypopigmented as a result of TAC treatment.
Other drawbacks of steroid injections include a risk for herpes zoster or telangiectasia. Overinjection can produce hypotrophic or divoted appearance.
The long-term effectiveness of TAC varies. In some patients, a scar treated with Kenalog stays flattened for more than a year. In other cases, patients require additional maintenance treatments before that point.
For patients with light-colored skin and small keloids, cryotherapy with a spray technique is a preferred treatment option. This involves spraying liquid nitrogen from a cryogen gun to achieve selective cell destruction. The drawbacks of this technique are hypopigmentation of the area treated and an inability of the spray to fully penetrate the entire depth of the keloid.4
For patients with darker skin and larger keloids, consider intralesional cryotherapy. This technique avoids epidermal depigmentation because it does not require a spraying of the epidermis. Instead, it involves penetrating a wide-bored spinal needle 2 cm into the keloid.5 The nozzle of the cryogen container is connected to the spinal needle, which is inserted parallel to the skin's surface. Scars greater than 2 cm in width should be treated with multiple needles dispersed evenly in a direction perpendicular to the skin.6 This delivers liquid nitrogen uniformly throughout the lesion.6
Radiation administered via electron beam is another treatment option. This method does not penetrate deep enough to affect internal organs. Orthovoltage radiation penetrates sufficiently and seems to yield better results.2
The use of radiation therapy in the treatment of benign lesions like keloids is controversial. However, research has concluded that radiation can aid in the treatment of keloids without producing dangerous side effects.4
For prevention, imiquimod (Aldara) is often an option. Imiquimod is a local immune response modifier that has strong antiviral and antitumor activity. Endogenous cytokine production activates innate and acquired immune responses.7 Aldara may be used to prevent new keloids from forming in patients who have a predetermined propensity. The topical application of imiquimod 5% cream after surgery reduces the likelihood of keloid recurrences.8
In patients with traumatized skin, Aldara should be initiated 1 to 2 weeks after the trauma. For example, a patient who has undergone excision and suturing should begin dosing after the sutures are removed.
Another option, 5-fluorouracil (5-FU), is thought to decrease postoperative scarring by reducing fibroblast proliferation. 5-FU can be used as monotherapy. Initial injections are provided weekly. For maintenance, injections should be scheduled every 4 to 6 weeks.4 Common side effects include pain and hyperpigmentation. Occasionally, ulceration can occur.9 One study found that 5-FU is initially effective on keloids but that 47% of patients experienced recurrence.10
TAC (10 mg/mL) 0.1 mL can be added to 0.9 mL of 5-FU (50 mg/mL) to reduce pain and inflammation. The mixture should be injected until the endpoint of slight blanching is observed.4
Some evidence suggests that the most effective role for 5-FU in the treatment of scars is in combination with other modalities. One study found neither 5-FU as monotherapy nor 5-FU with TAC was as effective as the combination of 5-FU, TAC and pulsed-dye laser.11
Multiple jet injections of 0.1 mL bleomycin (1.5 IU/mL) for keloids have been studied.12 Injection sites were spaced 0.5 mm apart, and injections were performed once each month. The treatment reduced mean scar height and improved scar erythema and pliability. The pain and pruritis associated with the keloids also decreased significantly.
Side effects included hyperpigmentation and skin atrophy. Unlike the treatments previously discussed, the researchers noted no recurrences at the final follow-up visit 19 months later.12
Interferon alpha-2b is an antiproliferative and an antifibrotic cytokine. It aids in keloid management via its aptitude for fibroblast proliferation and collagen synthesis interference.13
Mederma, Neosporin Scar Solution and Curad Scar Therapy Pads are a few over-the-counter choices for scar reduction. These products require daily application, and most people notice a result after about 1 month of use.
Mederma's active ingredient is allium cepa, which has a bioflavonoid that is an antihistamine. This bioflavonoid also has antiproliferative effects on malignant and normal cells. These qualities are helpful in overturning the proliferative and inflammatory reactions associated with hypertrophic scars.14
The active ingredient in Neosporin Scar Solution is silicone, and the active ingredient in Curad Scar Therapy is polyurethane. Both products are delivered using self-adhesive pads and can minimize the appearance of minor scars.
Additional options are available for patients who want to treat scars at home. Research has demonstrated the efficacy of hydrogel (Avogel) and 2% salicylic acid cream (Avosil) in limiting scar formation. The exact mechanism of action is unknown, but these products may induce scar hypoxia, increase scar temperature and cause increased hydration of the epidermis covering the scar.15
None of the options discussed thus far treat the erythema associated with keloid and hypertrophic scars. For that, a pulsed-dye laser is the most effective choice.
The vbeam by Candela Corporation is a pulsed-dye laser that has a wavelength of 595 nm. The vbeam targets hemoglobin, thereby collapsing the vessels that are feeding the keloid's blood supply.4
In a pulsed-dye laser regimen, scars are treated every 4 weeks and typically require three to five treatments. Pain is minimal. Purpura is a common side effect. At the end of a treatment series, scars typically appear less red, which allows for improved blending with natural skin color.
Surgical excision of keloid and hypertrophic scars is not recommended.
Acne Scars
Acne scars are classified in three categories: ice pick, boxcar and rolling. Treatment protocol is determined by the scar classification.16
Ice pick scars are deep, sharply demarcated and narrow in width (<2 mm). They are the deepest acne scars. Ice pick scars are widest at the skin's surface and taper at the deepest point.
Boxcar scars are square, oval or round depressions with sharply defined vertical perimeters. Unlike ice pick scars, they do not taper at the apex, and they are larger in width than ice pick scars.
Boxcar scars may be shallow (0.1 to 0.5 mm) or deep (>0.5 mm). Rolling scars are wider than 4 mm to 5 mm and result from dermal tethering. The rolling appearance is the result of abnormal fibrous anchoring of the dermis.16
Treatment Options
Both ice pick scars and deep boxcar scars can benefit from punch excision. This procedure involves using a punch biopsy instrument that matches the diameter of the scar. The provider punches out the scar tissue, excises it with scissors and closes the site with one or two 6-0 polypropylene sutures. Sutures are removed 7 days later. The area will have a linear scar, but it will be less noticeable than the previous scar.16
This treatment, known as subcision, disengages the tethering fibrous bands that cause rolling scars. The provider inserts an 18-gauge, 1-inch NoKor needle parallel to the skin's surface with the blade facing upward. Fibrous bands are released by moving the needle in a gentle pistonlike motion. Bacitracin and compression bandages are necessary after the procedure.16 Expected side effects include bruising, swelling and bleeding.
Dermabrasion may be performed on scarred areas using small, handheld dermabraders with end pieces such as serrated wheels, diamond fraises and wire brushes. These units generate speeds of 18,000 to 35,000 revolutions per minute.17 Dermabrasion may also be performed manually in a procedure called dermasanding, which entails the use of sterile sandpaper.18 Dermabrasion used to be the treatment of choice for skin resurfacing, but due to its postoperative complications, newer procedures have taken its place.16
Superficial chemical peels and microdermabrasion are not very effective in the treatment of acne scars because they do not penetrate deep enough into the dermis. However, medium-depth peels with Jessner's solution or trichloroacetic acid (TCA) 35% are safe and effective acne scar treatments.19
Diode lasers offer another treatment option. This type of laser stimulates the growth of new collagen and remodels existing collagen by activating the body's natural healing response. It does this by heating the water in the upper dermis, inducing a mild thermal injury that stimulates collagen synthesis.20 In the case of acne scars, it raises the divots and makes the skin appear smoother. The Smoothbeam by Candela Corporation is a diode laser that has a wavelength of 1450 nm. It has an FDA-approved indication for the treatment of acne and was the first laser to receive this indication.
In addition to acne and acne scars, the Smoothbeam can be used to treat fine lines and wrinkles. This treatment option requires little to no downtime because the epidermis is left intact. Four treatments are recommended, spaced 3 to 4 weeks apart. This type of laser treatment can be painful, so a topical anesthetic and the Zimmer chiller device should be used to reduce sensation.
Fractional photothermolysis is another option. This procedure, performed with lasers such as the Reliant 1550 nm Fraxel SR, creates microscopic thermal wounds to achieve rejuvenation of the skin with less risk and down time than traditional ablative laser resurfacing. Microscopic injuries are made to achieve homogenous thermal damage that results in skin tightening.21 Since the stratum corneum remains intact, there is much less risk for infection, scarring, hyperpigmentation or hypopigmentation. All skin colors are candidates for the procedure.
A full-face treatment with the Fraxel SR takes approximately 1 hour. Most patients experience immediate erythema and edema lasting 3 to 5 days. Since only 20% to 25% of the skin's surface is targeted with each Fraxel treatment, one treatment is usually not sufficient to adequately treat acne scars. In most cases, four to five treatments are required at 2- to 4-week intervals. To prevent hyperpigmentation, patients with darker skin tones should be pretreated with topical hydroquinone.
Shallow boxcar scars and residual scars from excisions benefit from laser skin resurfacing with a carbon dioxide (CO2) or an erbium:YAG (Er:YAG) laser.16 These lasers actually ablate (remove) the epidermis, resulting in a more uniform appearance of the skin. Because the protective layer of skin is removed, treatments with these lasers require significant downtime (reepithelialization takes 7 to 10 days) and are associated with a greater risk for infection, scarring and pigment changes. This procedure is usually limited to lighter skin types.
Retinoic acid, a derivative of vitamin A, can improve the appearance of acne scars. Studies show that when it is applied daily for 4 months, skin elasticity increases significantly due to realignment of dermal collagen bundles. This increase in papillary dermal collagen and elasticity leads to enhanced skin firmness and dermal architecture, which in turn means an improvement in appearance.22 Topical medications in this category include tretinoin (Retin A), tazarotene (Tazorac) and adapalene (Differin). In my experience, Tazorac tends to produce the best clinical results.
Medical needling, also called collagen induction therapy, is another treatment option for patients with acne scars. Medical needling is performed using a sterile roller equipped with multiple fine needles (Cosmetic Roll-Cit by Environ, Dermaroller by Horst Liebl Co.). The provider rolls the apparatus back and forth across the scarred area, causing punctures in the skin. These minuscule injuries to the dermis initiate the wound healing cascade. Results are evident 3 to 9 months after the treatment, since the body needs time to create new collagen.23
Dermal fillers function as the name states: They fill in the dermis. In the case of acne scars, these substances can fill in pitted areas so that the skin's surface appears level. Temporary, semipermanent and permanent dermal fillers are available.
Collagen is an example of a temporary filler. It is available in bovine (Zyderm and Zyplast) and human (Cosmoderm and Cosmoplast) forms. The results of these collagens last about 2 to 3 months.
Another example of a temporary filler is hyaluronic acid (Restylane and Captique). Hyaluronic acid is a synthetic material derived from a plant source. Because it is a larger molecule than collagen, its effects last longer, usually 6 to 9 months. Silicone is a permanent filler.
In most cases, the microdroplet technique is performed. The provider injects small amounts of the product over a series of visits.
Flat Surgical Scars
For flat scars resulting from surgery, two options are common and effective: fractional laser resurfacing and OTC gels and pads.24 These treatments are outlined earlier in this article.
Red Scars
As their name suggests, red scars appear as reddened areas on the skin. They can be treated with pulsed-dye lasers (discussed in the section on keloid and hypertrophic scars) or with intense pulsed-light (IPL) lasers. IPL lasers take aim at the red discoloration in scars by reducing the effects of excess hemoglobin. This treatment is associated with less purpura risk than pulsed-dye laser treatment.25
Hypopigmented Scars
Hypopigmented scars are lighter than surrounding skin. Most scars start pink or red and gradually fade to white. Once the scar has turned white, neither IPL nor pulsed-dye lasers have much effect.
A more useful option is narrow-band ultraviolet B (ReLume by Lumenis) to repigment hypopigmented scars. This method "tans" the lighter skin so that it better matches the surrounding skin. However, it does not affect texture, which means that the skin's color will blend better, but the texture will still look rough.
Narrow-band ultraviolet B treatment for hypopigmented areas requires one to six to 10 treatments to achieve base color, and they are usually scheduled once or twice weekly. The results are not permanent, so maintenance sessions are needed once a month thereafter.
Permanent makeup or camouflage tattoos are options to permanently repigment the skin. These interventions better blend the scar with the rest of the skin's surface and are most appropriate for small scars.
Hyperpigmented Scars
Hyperpigmented skin is darker than the rest of the skin. Postinflammatory hyperpigmentation (PIH) can occur after any skin trauma. Although many patients refer to their PIH spots as scars, they are not true scars because the connective tissue is not damaged. PIH is considered a temporary hyperpigmented discoloration.
The most common skin lightening agent is hydroquinone (Ultraquin, Lustra, etc.). It treats hyperpigmentation by inhibiting the enzyme tyrosinase, inhibiting DNA and RNA synthesis, destroying melanocytes and degrading melanosomes. It is prepared in concentrations of 1% to 12%, and concentrations of 4% and higher are available by prescription only. Absorption can be enhanced by combining hydroquinone with retinoids, vitamin C, salicylic acid or glycolic acid.
Methimazole (Tapazole), a peroxidase inhibitor, is a newer treatment for PIH. It is noncytotoxic and inhibits melanin production in cultured B16 melanocytes. Unlike most other lightening agents, methimazole is neither cytotoxic nor mutagenic.26
Kojic acid and azelaic acid are other agents available for skin lightening.
Chemical peels are another option for PIH. The Vitalize peel by Skin Medica incorporates alpha hydroxy acid, retinoic acid and other peeling agents. The purpose of this 20-minute procedure is to peel off the top layer of skin, thereby peeling off the brown spots as well. Patients notice a difference after one treatment, but a series is recommended for optimal results.
The skin begins peeling 2 days after the procedure and continues for 3 days. So if a patient schedules a peel on a Thursday, her peeling would begin on Saturday and last through Monday.
Another choice for PIH is depigmentation treatment. The Cosmelin line features a formula that blocks tyrosinase, the basic enzyme in melanin development. It does so by inverting the metabolic process of the transformation chain. The provider applies a mask to the skin in the office, and the patient washes it off 9 hours later. The next day, the patient's skin looks and feels sunburned, and this appearance typically lasts 5 days. After the redness disappears, more even skin tone is evident. Many patients report that their skin's overall appearance improves: Their pores are smaller and fine lines and wrinkles are diminished.
IPL is an option for PIH as well. IPL uses light energy that is absorbed solely by the unwanted melanin. The light heats the pigment, causing shattering or fragmenting of the melanin. These fragmented melanin particles are removed by phagocytosis. This procedure takes 15 to 30 minutes. After the treatment, the brown spots immediately appear darker and crusty; results are evident 5 to 7 days later.
Putting It Into Practice
The treatments discussed in this article may each be effective when used alone, but most outcomes are better with a combination approach. These treatments aid in scar reduction but rarely completely eradicate the scar. Hence, proper patient selection is vital — as are realistic patient expectations.
References
1. Hill MJ, ed. Dermatologic Nursing Essentials: A Core Curriculum. 2nd ed. Pittman, N.J.: Anthony J. Jannetti Inc.; 2003: 27, 144-145.
2. Mammino J. Keloids and hypertrophic scars. Available at: http://www.beauty4skin.com/keloids_hypertrophic_scars.shtml. Accessed Jan. 24, 2007.
3. Fitzpatrick TB, et al, eds. Color Atlas & Synopsis of Clinical Dermatology. 4th ed. New York: Mcgraw-Hill; 2001: 206-207.
4. Mutalik S. Treatment of keloids and hypertrophic scars. Indian J Dermatol Venereol Leprol. 2005;71(1):3-8.
5. Weshahy AH. Intralesional cryosurgery. A new technique using cryoneedles. J Dermatol Surg Oncol. 1993;19(2):123-126.
6. Gupta S, Kumar B. Intralesional cryosurgery using lumbar puncture and/or hypodermic needles for large, bulky, recalcitrant keloids. Int J Dermatol. 2001;40(5):349-353.
7. Urosevic M, et al. Mechanisms underlying imiquimod-induced regression of basal cell carcinoma in vivo. Arch Dermatol. 2003;139(10):1325-1332.
8. Berman B, Villa A. Imiquimod 5% cream for keloid management. Dermatol Surg. 2003;29(10):1050-1051.
9. Gupta S, Kalra A. Efficacy and safety of intralesional 5-fluorouracil in the treatment of keloids. Dermatology. 2002;204(2):130-132.
10. Kontochristopoulos G, et al. Intralesional 5-fluorouracil in the treatment of keloids: an open clinical and histopathologic study. J Am Acad Dermatol. 2005;52(3 pt 1):474-479.
11. Asilian A, et al. New combination of triamcinolone, 5-fluorouracil, and pulsed-dye laser for treatment of keloid and hypertrophic scars. Dermatol Surg. 2006;32(7):907-915.
12. Saray Y, Gulec AT. Treatment of keloids and hypertrophic scars with dermojet injections of bleomycin: a preliminary study. Int J Dermatol. 2005;44(9):777-784.
13. Davison SP, et al. Ineffective treatment of keloids with interferon alpha-2b. Plast Reconstr Surg. 2006;117(1):247-252.
14. Saulis AS, et al. Effect of Mederma on hypertrophic scarring in the rabbit ear model. Plast Reconstr Surg. 2002;110(1):177-183.
15. Danielson JR, Walter RJ. Case studies: use of salicylic acid (Avosil) and hydrogel (Avogel) in limiting scar formation. J Burns Wounds. 2005;28(4):93-100.
16. Jacob CI, et al. Acne scarring: a classification system and review of treatment options. J Am Acad Dermatol. 2001;45(1):109-117.
17. Gold MH. Dermabrasion in dermatology. Am J Clin Dermatol. 2003;4(7):467-471.
18. Poulos E, et al. Effectiveness of dermasanding (manual dermabrasion) on the appearance of surgical scars: a prospective, randomized, blinded study. J Am Acad Dermatol. 2003;48(6):897-900.
19. Al-Waiz MM, Al-Sharqi AI. Medium-depth chemical peels in the treatment of acne scars in dark-skinned individuals. Dermatol Surg. 2002;28(5):383-387.
20. Moretti M. Candela introduces Smoothbeam skin renewal laser. Aesthetic Buyers Guide. Medical Insights Inc.: Aliso Viejo, Calif.; 2001.
21. Hasegawa T, et al. Clinical trial of a laser device called fractional photothermolysis system for acne scars. J Dermatol. 2006;33(9):623-627.
22. Harris DW, et al. Topical retinoic acid in the treatment of fine acne scarring. Br J Dermatol. 1991;125(1):81-82.
23. Ellenberger J, Trow R. Ameliorating peri-oral wrinkles and stretch marks: a new, non-invasive treatment protocol-collagen induction therapy. Vivida. Available at: http://www.vivida.co.za/products/medical/ind/rob.php. Accessed Jan. 24, 2007.
24. Behroozan DS. Fractional photothermolysis for the treatment of surgical scars: a case report. J Cosmet Laser Ther. 2006;8(1):35-38.
25. Bellew SG, et al. Comparison of intense pulsed light to 595-nm long pulsed dye laser for the treatment of hypertrophic surgical scars: a pilot study. J Drugs Dermatol. 2005;4(4):448-452.
26. Kasraee B, et al. Topical methimazole as a new treatment for postinflammatory hyperpigmentation: report of the first case. Dermatology. 2005;211(4):360-362.
Christine Erdmann is a family nurse practitioner who provides aesthetic services at the Laser Institute of Dermatology and European Skin Care in Santa Monica, Calif. For more information, contact her at christineerdmann@hotmail.com.
Common Scars and Their Treatments
Keloid Scars — start as firm, rubbery masses with telangiectasia and pink to red hue; often become irregularly shaped and hyperpigmented
Hypertrophic Scars — confined to injury site; typically asymptomatic but sometimes pruritic
Acne Scars — develop in ice pick, boxcar or rolling presentations as a result of severe acne
Flat Surgical Scars — flat demarcations that develop after surgery at the wound site
Red Scars — reddened skin at any wound site
Hypopigmented Scars — lighter than surrounding skin; most start pink and gradually fade to white
Hyperpigmented Scars — darker than surrounding skin
Triamcinolone acetonide, spray cryotherapy, intralesional cryotherapy, imiquimod, 5-fluorouracil, bleomycin, interferon alpha-2b, Mederma, Neosporin Scar Solution, Curad Scar Therapy Pads, pulsed-dye laser. Pulsed-dye laser is only therapy that treats associated erythema.
Triamcinolone acetonide, spray cryotherapy, intralesional cryotherapy, imiquimod, 5-fluorouracil, bleomycin, interferon alpha-2b, Mederma, Neosporin Scar Solution, Curad Scar Therapy Pads, pulsed-dye laser. Pulsed-dye laser is only therapy that treats associated erythema.
Punch excision, medium-depth peels with Jessner's solution or trichloroacetic acid, diode laser, fractional thermolysis, laser skin resurfacing with carbon dioxide or erbium:YAG laser, retinoic acid, collagen induction therapy, dermal fillers
Fractional laser resurfacing, Mederma, Neosporin Scar Solution, Curad Scar Therapy pads
Pulsed-dye lasers, intense pulsed-light lasers
Intense pulsed-light laser or pulsed-dye laser while scar is still pink; narrow-band ultraviolet B laser therapy for all stages. Permanent makeup or camouflage tattoo may be needed to permanently repigment skin.
Hydroquinone (sometimes in combination with retinoids, vitamin C, salicylic acid or glycolic acid), methimazole, kojic acid, azelaic acid, chemical peels, depigmentation treatment, intense pulsed-light laser
Triamcinolone acetonide, spray cryotherapy, intralesional cryotherapy, imiquimod, 5-fluorouracil, bleomycin, interferon alpha-2b, Mederma, Neosporin Scar Solution, Curad Scar Therapy Pads, pulsed-dye laser. Pulsed-dye laser is only therapy that treats associated erythema.
Triamcinolone acetonide, spray cryotherapy, intralesional cryotherapy, imiquimod, 5-fluorouracil, bleomycin, interferon alpha-2b, Mederma, Neosporin Scar Solution, Curad Scar Therapy Pads, pulsed-dye laser. Pulsed-dye laser is only therapy that treats associated erythema.
Punch excision, medium-depth peels with Jessner's solution or trichloroacetic acid, diode laser, fractional thermolysis, laser skin resurfacing with carbon dioxide or erbium:YAG laser, retinoic acid, collagen induction therapy, dermal fillers
Fractional laser resurfacing, Mederma, Neosporin Scar Solution, Curad Scar Therapy pads
Pulsed-dye lasers, intense pulsed-light lasers
Intense pulsed-light laser or pulsed-dye laser while scar is still pink; narrow-band ultraviolet B laser therapy for all stages. Permanent makeup or camouflage tattoo may be needed to permanently repigment skin.
Hydroquinone (sometimes in combination with retinoids, vitamin C, salicylic acid or glycolic acid), methimazole, kojic acid, azelaic acid, chemical peels, depigmentation treatment, intense pulsed-light laser
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