During the mid-twentieth century, dermatologists realized that no single hypothesized factor (sebum, bacteria, or excess keratin) fully accounted for the disease in its entirety. This led to the current understanding that acne could be explained by a sequence of related events, beginning with blockage of the skin follicle by excessive dead skin cells, followed by bacterial invasion of the hair follicle pore, changes in sebum production, and inflammation.The approach to acne treatment underwent significant changes during the twentieth century. Retinoids became a medical treatment for acne in 1943. Benzoyl peroxide was first proposed as a treatment in 1958 and remains a staple of acne treatment. The introduction of oral tetracycline antibiotics (such as minocycline) modified acne treatment in the 1950s. These reinforced the idea amongst dermatologists that bacterial growth on the skin plays an important role in causing acne. Subsequently, in the 1970s, tretinoin (original trade name Retin A) was found to be an effective treatment. The development of oral isotretinoin (sold as Accutane and Roaccutane) followed in 1980. After its introduction in the United States, scientists identified isotretinoin as a medication highly likely to cause birth defects if taken during pregnancy. In the United States, more than 2,000 women became pregnant while taking isotretinoin between 1982 and 2003, with most pregnancies ending in abortion or miscarriage. Approximately 160 babies were born with birth defects due to maternal use of isotretinoin during pregnancy.Treatment of acne with topical crushed dry ice, known as cryoslush, was first described in 1907 but is no longer performed commonly.
The sixth-century Greek physician Aëtius of Amida reportedly coined the term "ionthos" (ίονθωξ,) or "acnae", which seems to be a reference to facial skin lesions that occur during "the acme of life" (puberty).In the 16th century, the French physician and botanist François Boissier de Sauvages de Lacroix provided one of the earlier descriptions of acne. He used the term "psydracia achne" to describe small, red, and hard tubercles that altered a persons facial appearance during adolescence and were neither itchy nor painful.The recognition and characterization of acne progressed in 1776 when Josef Plenck (an Austrian physician) published a book that proposed the novel concept of classifying skin diseases by their elementary (initial) lesions. In 1808 the English dermatologist Robert Willan refined Plencks work by providing the first detailed descriptions of several skin disorders using morphologic terminology that remains in use today. Thomas Bateman continued and expanded on Robert Willans work as his student and provided the first descriptions and illustrations of acne accepted as accurate by modern dermatologists. Erasmus Wilson, in 1842, was the first to make the distinction between acne vulgaris and rosacea. The first professional medical monograph dedicated entirely to acne was written by Lucius Duncan Bulkley and published in New York in 1885.Scientists initially hypothesized that acne represented a disease of the skins hair follicle, and occurred due to blockage of the pore by sebum. During the 1880s, they observed bacteria by microscopy in skin samples from people with acne. Investigators believed the bacteria caused comedones, sebum production, and ultimately acne.