Isotretinoin is an oral retinoid that is very effective for severe nodular acne, and moderate acne that is stubborn to other treatments. One to two months use is typically adequate to see improvement. Acne often resolves completely or is much milder after a 4–6 month course of oral isotretinoin. After a single course, about 80% of people report an improvement, with more than 50% reporting complete remission. About 20% of patients require a second course. Concerns have emerged that isotretinoin use is linked with an increased risk of adverse effects, like depression, suicidality, anemia, although there is no clear evidence to support some of these claims. Isotretinoin is superior to antibiotics or placebo in reducing acne lesions. The frequency of adverse events was about twice as high with isotretinoin, although these were mostly dryness-related events. No increased risk of suicide or depression was conclusively found. Isotretinoin use in women of childbearing age is regulated due to its known harmful effects in pregnancy. 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 birth control. In 2008, the United States started the iPLEDGE program to prevent isotretinoin use during pregnancy. iPledge requires the woman under consideration for isotretinoin therapy to have two negative pregnancy tests and mandates the use of two types of birth control for at least one month before therapy begins and one month after therapy is complete. The effectiveness of the iPledge program has been questioned due to continued instances of contraception nonadherence.
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. Notable adverse effects of microneedling include postinflammatory 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.
Ablative lasers deliver an intense wavelength of light to the skin, removing thin outer layers of the skin (epidermis). In addition, collagen production is stimulated in the underlying layer (the dermis). Patients are typically numbed with local anesthetic and the ablation is done as an outpatient procedure. CO2 and erbium are the ablative lasers most often used for acne scar treatment.
Diet. Studies indicate that certain dietary factors, including skim milk and carbohydrate-rich foods — such as bread, bagels and chips — may worsen acne. Chocolate has long been suspected of making acne worse. A small study of 14 men with acne showed that eating chocolate was related to a worsening of symptoms. Further study is needed to examine why this happens and whether people with acne would benefit from following specific dietary restrictions.