Acne is a common dermatological condition that affects millions of individuals around the world regardless of age, gender, or ethnicity, though it is most prevalent during adolescence when the body undergoes significant hormonal changes. It primarily manifests as a chronic inflammatory skin disorder involving the pilosebaceous unit, which consists of the hair follicle, sebaceous gland, and accompanying ducts. Acne typically appears on areas of the skin with the most sebaceous (oil) glands, including the face, chest, back, and shoulders. While acne is often viewed as a minor skin problem, its effects go far beyond physical appearance, impacting self-esteem, emotional well-being, and overall quality of life.

The development of acne is attributed to a complex interplay of several factors, including increased sebum production, hyperkeratinization of hair follicles, proliferation of Cutibacterium acnes (formerly Propionibacterium acnes), and inflammatory responses. Hormonal fluctuations, particularly androgens, stimulate the sebaceous glands to produce more oil, which combines with dead skin cells to clog pores. This creates an anaerobic environment 下巴暗瘡 for the proliferation of bacteria, triggering inflammation and the formation of various types of acne lesions, such as comedones (blackheads and whiteheads), papules, pustules, nodules, and cysts. Genetic predisposition also plays a crucial role in acne development, with studies showing that individuals with a family history of acne are more likely to experience it themselves.

External factors such as diet, stress, pollution, and the use of certain cosmetics or medications can exacerbate the condition. Although chocolate and greasy foods were historically blamed for acne, current research suggests that high-glycemic-index foods, dairy products, and diets rich in sugar may contribute to its severity by influencing insulin and androgen levels. Psychological stress is another recognized trigger, as it can worsen inflammation and disrupt hormonal balance. Additionally, friction or pressure on the skin, known as acne mechanica, can result from helmets, backpacks, or tight clothing. Diagnosing acne is typically straightforward based on the clinical presentation and patient history, though severity can range from mild to severe and scarring.

Treatment for acne varies depending on its type and intensity, and includes topical, oral, procedural, and lifestyle-based interventions. Topical agents like benzoyl peroxide, salicylic acid, retinoids, and antibiotics are commonly used to reduce inflammation, unclog pores, and combat bacterial growth. Oral medications, such as antibiotics, hormonal therapies like birth control pills, anti-androgens like spironolactone, and isotretinoin (commonly known by the brand name Accutane), are prescribed for moderate to severe acne or cases unresponsive to topical treatments. While effective, isotretinoin requires close medical supervision due to its potential side effects, including birth defects, mood changes, and liver function abnormalities. Hormonal therapies are particularly beneficial for women whose acne is linked to menstrual cycles or hormonal imbalances like polycystic ovarian syndrome (PCOS).