What Causes Acne on the Chest and Back?

Acne on the chest and back—often referred to as truncal acne—is a common dermatologic concern that affects many adolescents and adults. Unlike facial acne, which tends to draw more immediate attention, truncal acne can be particularly frustrating due to its visibility under clothing, potential for scarring, and frequent recurrence.

This form of acne arises from the same fundamental pathophysiology as facial acne: follicular hyperkeratinization, excess sebum production, colonization by Cutibacterium acnes (formerly Propionibacterium acnes), and subsequent inflammation. However, the trunk has a higher density of sebaceous glands per unit area compared to most other body regions—especially the upper chest and upper back—making it especially prone to comedone formation and inflammatory lesions.

Several contributing factors may exacerbate or trigger truncal acne. These include hormonal fluctuations—particularly androgen-driven sebum stimulation—as seen in polycystic ovary syndrome (PCOS) or during puberty; occlusion from tight-fitting synthetic fabrics, backpacks, or sports equipment; excessive sweating combined with delayed showering after physical activity; and the use of comedogenic skincare or haircare products that migrate onto the skin (e.g., heavy oils, silicones, or pomades).

In some cases, persistent or atypical truncal acne warrants further evaluation. Lesions that are unusually painful, cystic, or resistant to standard therapy may suggest underlying conditions such as hidradenitis suppurativa, folliculitis decalvans, or even gram-negative folliculitis—especially following prolonged antibiotic use. Additionally, sudden-onset severe truncal acne in adult women may signal endocrine abnormalities requiring hormonal assessment.

Management typically begins with topical therapies—including benzoyl peroxide, retinoids (e.g., adapalene), or combination agents—and progresses to systemic treatments like oral antibiotics (e.g., doxycycline), hormonal therapy (e.g., combined oral contraceptives or spironolactone in appropriate candidates), or isotretinoin for severe, scarring, or refractory disease. Patient education on gentle cleansing, non-comedogenic product selection, and avoidance of mechanical irritation is equally critical to long-term control.