Patient Presentation
An 18-year-old male came to clinic for follow up of his acne. He had used benzoyl peroxide and a tretinoin cream with overall good results, but 6 months ago had worsening. He was started on a topical antibiotic and he reported that it was under better control. “My face isn’t as bad, and since I’ve been using the medicines on my back and shoulders those also aren’t so bad too,”” he said. He did think it got worse when he needed to wear protective sports equipment over his shoulders for baseball.

The pertinent physical exam revealed a healthy male with normal vital signs. He had mild closed comedomal acne along the lateral face and a few lesions on the upper back, shoulders and trunk. None looked particularly irritated. There was no evidence of nodules, cysts or scarring.

The diagnosis of a healthy male with improved moderate acne was made. His medications were refilled and he was reminded to use sunscreen and to followup at his next health maintenance visit. The medical student in the clinic said that he knew how the prescription medications worked to help acne, but was not sure about the benzoyl peroxide. “That’s over-the-counter so they didn’t talk much about it in our pharmacology class,” he noted. The attending replied, “What I remember is that it decreases the bacteria and it increases the turn over of the skin cells so it doesn’t plug up the follicle. It probably does something else, but I just remember a little bit of chemistry. Peroxides are used for cleaning and either kills or stops bacteria. Peroxides are a reactive chemical so could irritate the skin, and that helps me remember that they turn the skin over too.”

Discussion
Acne vulgaris is an inflammatory disorder of the pilosebaceous unit of the skin. It is an acute and chronic disease process. Common skin lesions include:

• Comedomal acne has comedomes
  • White heads = closed comedomes
  • Black heads = open comedomes
• Inflammatory acne has papules and pustules
• Nodulocystic acne has nodules and cysts

The lesions can be just a few to many and can cause hyperpigmentation and scarring. These lesions commonly affect the face, upper torso and upper arms. It can be found in all age groups and ethnic groups and is very common in adolescents.

Learning Point
The general mechanism of action is the pilosebaceous units hypersensitivity to androgens, in the presence of bacteria (Cutibacterium acnes previously Propionibacterium acnes which is part of the natural skin flora) causing inflammation. The pathological entities more specifically are increased sebum production, increased follicular hyperkeratinization, presence of Cutibacterium acnes, and inflammation. There are many proposed factors which appear to make acne worse such as certain medications, comedogenic topical products, skin trauma and different hormonal states. Common medications used and their primary mechanisms of action include:

• Benzoyl Peroxide
  • Mechanism of action:
    • Sebostatic (mild)
    • Keratolytic (mild)
    • Bactericidal and doesn’t seem to cause drug resistance
  • Use: mild to moderate comedomal acne, can be used by itself but best with other therapy
  • Forms: gel, cream, washes
  • Problems: hypersensitivity, erythema, peeling, bleaches clothing and fabric

• Tretinoin
  • Mechanism of action:
    • Keratinization modifier
    • Inflammation modifier
  • Use: mild to severe comedomal, inflammatory and nodular cystic acne
  • Form: gel, cream, lotion, solution
  • Problems: dry skin, peeling, burning, erythema, pain, photosensitivity
  • Ultraviolet light and environmental exposure can increase irritation

• Antibiotics
  • Topical
    • Clindamycin, erythromycin and similar
    • Mechanism of action:
      • Bacteriostatic effect
    • Use: mild to moderate comedomal and inflammatory acne
    • Form: gel, lotion, solution
    • Problems: if used by self can have bacterial resistance
  • Oral
    • Docycycline, minocycline, tetracycline and similar
    • Mechanism of action:
      • Bacteriostatic effect
    • Use: moderate to severe comedomal, inflammatory and nodular and cystic acne
    • Form: oral
    • Problems: with doxycycline include gastrointestinal, renal and hematologic problems, rashes and photosensitivity, other problems can be seen with other antibiotics

• Isotretinoin
  • Mechanism of action:
    • Sebum modifier
    • Keratinization modifier
  • Use: severe acne
  • Form: oral
  • Problems: usually prescribed by a dermatologist with special training. It is a known teratogen so special precautions and counseling must be adhered to if it is prescribed.

• Oral contraceptives for female patients
  • Mechanism of action:
    • Decreases sebum production
  • Use: moderate to severe acne
  • Form: oral
  • Problems: mood changes, weight gain, menstrual irregularities, other estrogen and androgen effects

The primary problems with treatment usually are adherence to the regimen, along with having appropriate expectations for results. Treatments needs to be consistent and continued for weeks to months to improve and manage the clinical course of the acne.

Questions for Further Discussion
1. What are criteria for referral to a dermatologist for acne?
2. How is neonatal acne the same or different than adolescent acne?
3. What patient education tips or tricks do you use to help your patients with medication adherence?

Related Cases

Disease: Acne

Symptom/Presentation: Papulosquamous Lesions

Specialty: Dermatology | Pharmacology / Toxicology

Age: Teenager

To Learn More
To view pediatric review articles on this topic from the past year check PubMed.

Evidence-based medicine information on this topic can be found at SearchingPediatrics.com and the Cochrane Database of Systematic Reviews. Information prescriptions for patients can be found at MedlinePlus for this topic: Acne

To view current news articles on this topic check Google News.

To view images related to this topic check Google Images.

To view videos related to this topic check YouTube Videos.

Matin T, Patel P, Goodman MB. Benzoyl Peroxide. In: StatPearls. StatPearls Publishing; 2025. Accessed March 17, 2025. http://www.ncbi.nlm.nih.gov/books/NBK537220/

Pile HD, Sadiq NM. Isotretinoin. In: StatPearls. StatPearls Publishing; 2025. Accessed March 17, 2025. http://www.ncbi.nlm.nih.gov/books/NBK525949/

Yoham AL, Casadesus D. Tretinoin. In: StatPearls. StatPearls Publishing; 2025. Accessed March 17, 2025. http://www.ncbi.nlm.nih.gov/books/NBK557478/

Sutaria AH, Masood S, Saleh HM, Schlessinger J. Acne Vulgaris. In: StatPearls. StatPearls Publishing; 2025. Accessed March 24, 2025. http://www.ncbi.nlm.nih.gov/books/NBK459173/

Author
Donna M. D’Alessandro, MD
Professor of Ped