Research Progress on the Pathogenesis, Immune and Inflammatory Mechanisms and Treatment of Acne

Abstract

Acne is a chronic inflammatory skin disease involving the pilosebaceous unit. Based on studies published from 2021 to 2025, this review summarizes recent progress in acne pathogenesis, immune inflammation, pharmacological treatment, and light- and energy-based therapies. It also briefly reviews the pathogenesis and external therapies of traditional Chinese medicine (TCM). Recent evidence suggests that excessive sebum production, altered lipid composition, follicular keratinization, skin barrier dysfunction, microbial dysbiosis, and immune responses promote one another. The strain types, biofilms, and metabolites of Cutibacterium acnes may better explain differences in inflammatory activity than the total bacterial load. TLR/NF-κB signaling, the NLRP3 inflammasome, neutrophil extracellular traps, and Th1/Th17 responses all contribute to acne inflammation. Topical retinoids, benzoyl peroxide, and appropriate antimicrobial therapy remain the main treatments. Oral isotretinoin may be considered for severe acne or patients at high risk of scarring. The 1726 nm laser, intense pulsed light, and photodynamic therapy are mainly used for active acne, whereas fractional lasers, microneedle radiofrequency, and fractional picosecond lasers are mainly used for atrophic scars. Treatment should be selected according to lesion type, disease severity, scarring risk, and patient tolerance.