Editing Acne (section)

====Retinoids====
[[Retinoids]] are medications that reduce inflammation, normalize the follicle [[Cell cycle|cell life cycle]], and reduce sebum production.<ref name=Das2014/><ref name="Riahi2016">{{cite journal | vauthors = Riahi RR, Bush AE, Cohen PR | title = Topical Retinoids: Therapeutic Mechanisms in the Treatment of Photodamaged Skin | journal = American Journal of Clinical Dermatology | volume = 17 | issue = 3 | pages = 265–76 | date = June 2016 | pmid = 26969582 | doi = 10.1007/s40257-016-0185-5 | s2cid = 12663356 | type = Review }}</ref> They are structurally related to [[vitamin A]].<ref name="Riahi2016"/> Studies show dermatologists and primary care doctors underprescribe them for acne.<ref name="Zaenglein2018"/> The retinoids appear to influence the cell life cycle in the follicle lining. This helps prevent the [[hyperkeratinization|accumulation of skin cells]] within the hair follicle that can create a blockage. They are a first-line acne treatment,<ref name=Vary2015/> especially for people with dark-colored skin. Retinoids are known to lead to faster improvement of postinflammatory hyperpigmentation.<ref name=Yin2014>{{cite journal | vauthors = Yin NC, McMichael AJ | title = Acne in patients with skin of color: practical management | journal = American Journal of Clinical Dermatology | volume = 15 | issue = 1 | pages = 7–16 | date = February 2014 | pmid = 24190453 | doi = 10.1007/s40257-013-0049-1 | s2cid = 43211448 | type = Review }}</ref>

Topical retinoids include [[adapalene]], [[retinol]], [[retinaldehyde]], [[isotretinoin]], [[tazarotene]], [[trifarotene]], and [[tretinoin]].<ref name=Kong2013/><ref name="FDA Snapshot">{{cite web | title=Drug Trials Snapshots: Aklief | website=U.S. [[Food and Drug Administration]] (FDA) | date=11 October 2019 | url=https://www.fda.gov/drugs/resources-information-approved-drugs/drug-trials-snapshots-aklief | archive-url=https://web.archive.org/web/20191119042107/https://www.fda.gov/drugs/resources-information-approved-drugs/drug-trials-snapshots-aklief | archive-date=19 November 2019 | url-status=live | access-date=18 November 2019}}{{PD-notice}}</ref><ref>{{cite web|title=Isotretinoin|url=https://www.drugs.com/international/isotretinoin.html|access-date=2021-04-25|website=Drugs.com|archive-date=16 July 2018|archive-url=https://web.archive.org/web/20180716025017/https://www.drugs.com/international/isotretinoin.html|url-status=live}}</ref> They often cause an initial flare-up of acne and facial [[flushing (physiology)|flushing]] and can cause significant skin irritation. Generally speaking, retinoids increase the skin's [[Photosensitivity|sensitivity to sunlight]] and are therefore recommended for use at night.<ref name=Vary2015/> Tretinoin is the least expensive of the topical retinoids and is the most irritating to the skin, whereas adapalene is the least irritating but costs significantly more.<ref name=Vary2015/><ref name=Foti2015>{{cite journal | vauthors = Foti C, Romita P, Borghi A, Angelini G, Bonamonte D, Corazza M | title = Contact dermatitis to topical acne drugs: a review of the literature | journal = Dermatologic Therapy | volume = 28 | issue = 5 | pages = 323–9 | date = September 2015 | pmid = 26302055 | doi = 10.1111/dth.12282 | s2cid = 43870491 | type = Review | doi-access = free }}</ref> Most formulations of tretinoin are incompatible for use with benzoyl peroxide.<ref name="Zaenglein2018"/> Tazarotene is the most effective and expensive topical retinoid but is usually not as well tolerated.<ref name=Vary2015/><ref name=Foti2015/> In 2019 a tazarotene lotion formulation, marketed to be a less irritating option, was approved by the FDA.<ref>{{cite web|title=Arazlo lotion launched in US for acne treatment|url=https://www.healio.com/news/dermatology/20200623/arazlo-lotion-launched-in-us-for-acne-treatment|access-date=2021-03-10|website=Healio.com|archive-date=28 July 2021|archive-url=https://web.archive.org/web/20210728231130/https://www.healio.com/news/dermatology/20200623/arazlo-lotion-launched-in-us-for-acne-treatment|url-status=live}}</ref> Retinol is a form of vitamin A that has similar but milder effects and is present in many over-the-counter moisturizers and other topical products.

Isotretinoin is an oral retinoid that is very effective for severe nodular acne, and moderate acne that is stubborn to other treatments.<ref name="Vary2015" /><ref name="BMJ2013" /> One to two months of use is typically adequate to see improvement. Acne often resolves completely or is much milder after a 4–6&nbsp;month course of oral isotretinoin.<ref name="Vary2015" /> After a single round of treatment, about 80% of people report an improvement, with more than 50% reporting complete remission.<ref name="BMJ2013" /> About 20% of people require a second course, but 80% of those report improvement, resulting in a cumulative 96% efficacy rate.<ref name="BMJ2013" />

There are concerns that isotretinoin is linked to adverse effects, like [[major depressive disorder|depression]], [[suicidality]], and [[anemia]]. There is no clear evidence to support some of these claims.<ref name="Vary2015" /><ref name="BMJ2013" /> Isotretinoin has been found in some studies to be superior to antibiotics or placebo in reducing acne lesions.<ref name="Lew2018"/> However, a 2018 review comparing inflammatory lesions after treatment with antibiotics or isotretinoin found no difference.<ref>{{cite journal | vauthors = Costa CS, Bagatin E, Martimbianco AL, da Silva EM, Lúcio MM, Magin P, Riera R | title = Oral isotretinoin for acne | journal = The Cochrane Database of Systematic Reviews | volume = 11 | pages = CD009435 | date = November 2018 | issue = 2 | pmid = 30484286 | pmc = 6383843 | doi = 10.1002/14651858.cd009435.pub2 }}</ref> The frequency of adverse events was about twice as high with isotretinoin use, although these were mostly dryness-related events.<ref name="Lew2018" /> No increased risk of suicide or depression was conclusively found.<ref name="Lew2018" />

Medical authorities strictly regulate isotretinoin use in women of childbearing age due to its known [[teratogenicity|harmful effects in pregnancy]].<ref name="BMJ2013" /> For such a woman to be considered a candidate for isotretinoin, she must have a confirmed negative [[pregnancy test]] and use an effective form of [[contraception|birth control]].<ref name="BMJ2013" /> In 2008, the United States started the [[iPLEDGE]] program to prevent isotretinoin use during pregnancy.<ref name="Tan2016" /> iPLEDGE requires the woman to have two negative pregnancy tests and to use two types of birth control for at least one month before isotretinoin therapy begins and one month afterward.<ref name="Tan2016" /> The effectiveness of the iPLEDGE program is controversial due to continued instances of contraception nonadherence.<ref name="Tan2016">{{cite journal | vauthors = Tan J, Boyal S, Desai K, Knezevic S | title = Oral Isotretinoin: New Developments Relevant to Clinical Practice | journal = Dermatologic Clinics | volume = 34 | issue = 2 | pages = 175–84 | date = April 2016 | pmid = 27015777 | doi = 10.1016/j.det.2015.11.002 | type = Review }}</ref><ref name="Pre2013">{{cite journal | vauthors = Prevost N, English JC | title = Isotretinoin: update on controversial issues | journal = Journal of Pediatric and Adolescent Gynecology | volume = 26 | issue = 5 | pages = 290–3 | date = October 2013 | pmid = 24147278 | doi = 10.1016/j.jpag.2013.05.007 | type = Review }}</ref>