A 24-year-old woman comes to the office due to worsening acne. Over the past 3 months, the patient has had frequent breakouts on the shoulders and upper back. She had acne on her face during puberty, which cleared spontaneously after several years, but has never before had symptoms on her trunk. The patient has no other medical conditions, and her only medication is a combination oral contraceptive. She has been training for a half-marathon for the past 4 months and has lost 6.8 kg (15 lb) during this period. She does not use tobacco, alcohol, or illicit drugs, and she relocated from California to Wisconsin for work a year ago. Vital signs are within normal limits. Physical examination shows acneiform eruptions on the shoulders and mid-back. Which of the following is most likely contributing to worsening of this patient's acne?
Acne vulgaris | |
Clinical features |
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Pathogenesis |
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Risk factors |
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Acne vulgaris is a disorder of the pilosebaceous follicle. Hyperkeratinization and obstruction of the follicle in combination with glandular enlargement and increased sebum production provides an optimal environment for Cutibacterium (Propionibacterium) acnes. This organism metabolizes sebaceous lipids, releasing inflammatory factors that lead to follicular and perifollicular inflammation. Acne is most common in areas with a high concentration of sebaceous follicles, including the face, back, chest, and upper arms.
Androgens stimulate production of sebum, and increased androgen levels (eg, puberty, polycystic ovary syndrome) increase the incidence of acne. Obstruction of the glands, such as by oil-based hair products (pomade acne), also promotes acne. In addition, mechanical irritation can promote acne by increasing glandular occlusion and disruption of follicles (acne mechanica). Sports participation, as in this patient, frequently triggers acne due to the use of tight-fitting clothing (eg, sports bras) and protective gear (eg, helmets).
(Choice A) High ambient temperatures can worsen acne, leading to formation of painful nodules on the trunk (tropical acne). Colder temperatures are not associated with acne.
(Choice B) Exposure to water contaminated with Pseudomonas aeruginosa can cause erythematous papules and pustules around hair follicles (hot-tub folliculitis). This condition begins acutely, resolves spontaneously within 1-2 weeks, and typically involves the skin under a bathing suit (eg, buttocks) or on the extremities.
(Choice C) Obesity is associated with an increased risk of acne, but weight loss generally does not worsen acne.
(Choice D) Typical oral contraceptives do not promote acne. Rather, many commonly used contraceptives can reduce acne due to decreased synthesis of androgens.
Educational objective:
Risk factors for acne include increased androgen levels; obstruction of pilosebaceous glands by oil-based hair products; and mechanical irritation of skin follicles. Sports participation frequently triggers acne due to the use of tight-fitting clothing and protective gear.