Acne is a common skin disorder among young people, affecting up to 85% of adolescents, often causing a significant amount of distress, and, when severe, it can have long-lasting effects.
Pathophysiology
Acne vulgaris involves four processes: sebaceous hyperplasia driven by increased androgen levels; alterations of follicular growth and differentiation; colonization of follicle by Propionibacterium acnes; and immune response and inflammation.
Categorization
Categorizing acne on the basis of morphology and severity of lesions is useful. The three basic morphologies are comedonal, inflammatory, and mixed. Comedones are closed (whitehead) or open (blackhead). Closed comedones result from cell proliferation mixing with sebum and partially clogging the follicular lumen. Open comedones result when the follicle has a broader opening with visible keratin buildup that darkens. Inflammation manifests as papules, pustules, nodules, or pseudocysts and may include scarring or sinus tracts. The inflammation results from P. acne colonization, with release of inflammatory mediators. Severity is classified as mild, moderate, and severe. This assessment is subjective but should be based on number and type of lesions, amount of skin involved, scarring, and risk of dyspigmentation, which is greater in darker skin.
Age-specific considerations
The differential diagnosis and work-up of acne varies by age group. Neonatal (birth-6 weeks) acne has a prevalence of 20%, though these lesions actually may represent acneiform conditions such as self-limited neonatal cephalic pustulosis or transient neonatal pustular melanosis.
Photo courtesy of Neil Skolnik, M.D.
Dr. Neil Skolnik and Dr. Alison Lee
Infantile (6 weeks to 12 months, or uncommonly up to a few years old) acne is more common in males, usually is comedonal and inflammatory, and presents with papules, pustules, or nodules. A work-up usually is not necessary unless growth is abnormal or signs of hirsutism/virilization exist, in which case referral to endocrinology is made for a possible hormonal anomaly. Of note, true infantile acne may portend an increased risk of severe adolescent acne.
Mid-childhood (1-7 years) acne is not common since this age group does not produce significant levels of adrenal or gonadal androgens. If it does occur, a work-up by an endocrinologist is recommended.
Preadolescent (7-12 years) acne is common and may be the first sign of pubertal maturation. Such acne usually is comedonal with a "T-zone" distribution (forehead and central face), and may appear on the ears. Inflammatory lesions are sparse. No work-up beyond history and physical is needed unless there is concern for endocrinologic abnormalities (for example, PCOS), which may manifest as very severe or refractory acne.
Treatment
Goals of treatment involve addressing pathogenic factors and using the least aggressive but effective regimen, while avoiding bacterial resistance development. Additionally, side effects and expectations of results (in other words, noticeable results may take 4-8 weeks for any acne treatment) should be discussed in order to enhance compliance.
Various over-the-counter (OTC) products and prescription agents are available for the treatment of acne. OTC agents that have been tested include salicylic acid and benzoyl peroxide (BP). BP is effective, safe, and inexpensive. It can be used as monotherapy and, when used in combination with topical or systemic antibiotics, may minimize antibiotic-resistant P. acnes development.
Prescription options include topical retinoids, topical antibiotics, topical dapsone, oral antibiotics (typically tetracycline, doxycycline, or minocycline), oral isotretinoin, fixed-dose combination topical agents (BP/topical antibiotic, BP/topical retinoid, and topical retinoid/antibiotic), and hormonal therapy. The recommendations address the treatment of mild, moderate, and severe pediatric acne.
Mild acne usually presents as comedonal or mixed. Initial treatment can include BP monotherapy, topical retinoids, or combinations of topical retinoids, antibiotics, and BP. In patients of color, where there is a greater risk of scarring and dyspigmentation, initial therapy might also include a topical or oral antibiotic. In cases of inadequate response, the concentration, type, or formulation of topical retinoid can be changed or the topical combination can be modified.
Moderate acne may require an aggressive regimen of combination topical therapy that includes a retinoid and BP with or without topical dapsone, with the likely addition of an oral antibiotic. If lesions are moderate to severe inflammatory or mixed, oral antibiotics are effective, with maximal response taking 3-6 months. If an inadequate response and adherence assured, the strength, type, and formulation of topical regimens can be adjusted, although referral to a specialist may be considered.
Severe acne requires prompt initiation of treatment to avoid scarring and permanent skin changes. Treatment should include oral antibiotics with topical retinoids plus BP, with or without topical antibiotics. Strong consideration should be given to adding hormonal therapy to the treatment regimen of young menstruating women who have severe acne. In addition, for both males and females, oral isotretinoin and referral to a specialist may be considered.