Editing Acne (section)

====Postacne scar treatment====
[[Dermabrasion]] is an effective therapeutic procedure for reducing the appearance of superficial atrophic scars of the boxcar and rolling varieties.<ref name="Levy2012"/> Ice-pick scars do not respond well to treatment with dermabrasion due to their depth.<ref name="Levy2012"/> The procedure is painful and has many potential side effects such as skin sensitivity to sunlight, [[erythema|redness]], and [[Hypopigmentation|decreased pigmentation of the skin]].<ref name="Levy2012"/> Dermabrasion has fallen out of favor with the introduction of laser resurfacing.<ref name="Levy2012"/> Unlike dermabrasion, there is no evidence that [[microdermabrasion]] is an effective treatment for acne.<ref name="Titus2012"/>

Dermal or subcutaneous [[Injectable filler|filler]]s are substances injected into the skin to improve the appearance of acne scars. Fillers are used to increase natural [[collagen]] production in the skin and to increase skin volume and decrease the depth of acne scars.<ref name="Soliman2018">{{cite journal | vauthors = Soliman YS, Horowitz R, Hashim PW, Nia JK, Farberg AS, Goldenberg G | title = Update on acne scar treatment | journal = Cutis | volume = 102 | issue = 1 | pages = 21;25;47;48 | date = July 2018 | pmid = 30138491 | url = https://www.mdedge.com/cutis/article/169785/acne/update-acne-scar-treatment | type = Review | access-date = 19 September 2018 | archive-url = https://web.archive.org/web/20180919132148/https://www.mdedge.com/cutis/article/169785/acne/update-acne-scar-treatment | archive-date = 19 September 2018 | url-status = live }}</ref> Examples of fillers used for this purpose include [[hyaluronic acid]]; [[poly(methyl methacrylate)]] [[microsphere]]s with collagen; human and bovine collagen derivatives, and fat harvested from the person's own body (autologous fat transfer).<ref name="Soliman2018"/>

[[Microneedling]] is a procedure in which an instrument with multiple rows of tiny needles is rolled over the skin to elicit a wound healing response and stimulate collagen production to reduce the appearance of atrophic acne scars in people with darker skin color.<ref name="Cohen2016">{{cite journal | vauthors = Cohen BE, Elbuluk N | title = Microneedling in skin of color: A review of uses and efficacy | journal = Journal of the American Academy of Dermatology | volume = 74 | issue = 2 | pages = 348–55 | date = February 2016 | pmid = 26549251 | doi = 10.1016/j.jaad.2015.09.024 | type = Review }}</ref> Notable adverse effects of microneedling include post-inflammatory hyperpigmentation and tram track scarring (described as discrete slightly raised scars in a linear distribution similar to a tram track). The latter is thought to be primarily attributable to improper technique by the practitioner, including the use of excessive pressure or inappropriately large needles.<ref name="Cohen2016"/><ref name="Pahwa2012">{{cite journal | vauthors = Pahwa M, Pahwa P, Zaheer A | title = "Tram track effect" after treatment of acne scars using a microneedling device | journal = Dermatologic Surgery | volume = 38 | issue = 7 Pt 1 | pages = 1107–8 | date = July 2012 | pmid = 22587597 | doi = 10.1111/j.1524-4725.2012.02441.x | type = Case Report & Literature Review }}</ref>

A clinical study assessing the efficacy of microneedling vis-à-vis with application of topical [[tazarotene]] gel, 0.1% in the treatment of postacne facial scars, found that tazarotene gel when applied for a period of three to six months once every night, resulted in significant improvement of atrophic scars similar to microneedling.<ref name="Tazarotene">{{cite journal |last1=Afra |first1=TP |last2=Razmi |first2=T M |last3=Narang |first3=T |last4=Dogra |first4=S |last5=Kumar |first5=A |title=Topical Tazarotene Gel, 0.1%, as a Novel Treatment Approach for Atrophic Postacne Scars: A Randomized Active-Controlled Clinical Trial |journal=JAMA Facial Plast Surg |date=2019 |volume=21 |issue=2 |pages=125–132 |doi=10.1001/jamafacial.2018.1404 |pmid=30452511|pmc=6439800 }}</ref>

[[Subcision]] is useful for the treatment of superficial atrophic acne scars and involves the use of a small needle to loosen the fibrotic adhesions that result in the depressed appearance of the scar.<ref>{{cite journal | vauthors = Lanoue J, Goldenberg G | title = Acne scarring: a review of cosmetic therapies | journal = Cutis | volume = 95 | issue = 5 | pages = 276–81 | date = May 2015 | pmid = 26057505 | type = Review }}</ref><ref>{{cite journal | vauthors = Kroepfl L, Emer JJ | title = Combination Therapy for Acne Scarring: Personal Experience and Clinical Suggestions | journal = Journal of Drugs in Dermatology | volume = 15 | issue = 11 | pages = 1413–1419 | date = November 2016 | pmid = 28095556 | type = Review }}</ref><ref>{{cite journal | vauthors = Zaleski-Larsen LA, Fabi SG, McGraw T, Taylor M | title = Acne Scar Treatment: A Multimodality Approach Tailored to Scar Type | journal = Dermatologic Surgery | volume = 42 Suppl 2 | issue = Supplement 2 | pages = S139-49 | date = May 2016 | pmid = 27128240 | doi = 10.1097/DSS.0000000000000746 | s2cid = 25638674 | type = Review }}</ref>

[[Chemical peel]]s can be used to reduce the appearance of acne scars.<ref name=Levy2012/> Mild peels include those using [[glycolic acid]], [[lactic acid]], [[salicylic acid]], [[Jessner's solution]], or a lower concentration (20%) of [[trichloroacetic acid]]. These peels only affect the [[epidermis|epidermal layer of the skin]] and can be useful in the treatment of superficial acne scars as well as skin pigmentation changes from inflammatory acne.<ref name=Levy2012/> Higher concentrations of trichloroacetic acid (30–40%) are considered to be medium-strength peels and affect the skin as deep as the [[Dermis#Stratum papillare|papillary dermis]].<ref name=Levy2012/> Formulations of trichloroacetic acid concentrated to 50% or more are considered to be deep chemical peels.<ref name=Levy2012/> Medium-strength and deep-strength chemical peels are more effective for deeper atrophic scars but are more likely to cause side effects such as skin pigmentation changes, infection, and [[Milium (dermatology)|small white superficial cysts known as milia]].<ref name=Levy2012/>