What are the causes and common myths of acne?

Causes of Acne and Common Myths

Acne is primarily caused by follicular hyperkeratinization, microbial colonization with Cutibacterium acnes (formerly Propionibacterium acnes), excess sebum production, and complex inflammatory mechanisms involving both innate and acquired immunity, as well as genetic and hormonal factors. 1

Established Causes of Acne

Biological/Physiological Factors:

• Follicular hyperkeratinization: Abnormal shedding of skin cells lining the follicle, causing blockage
• Microbial colonization: Primarily by Cutibacterium acnes bacteria 1
• Sebum overproduction: Stimulated by androgens and other hormones
• Inflammatory processes: Complex mechanisms involving both innate and acquired immunity 1
• Genetic predisposition: Family history of acne increases risk 1
• Hormonal factors:
  • Androgen excess (testosterone, DHEA-S)
  • Hormonal fluctuations, particularly during menstrual cycles 2
  • Conditions like polycystic ovarian syndrome (PCOS) 1, 3

Environmental and Lifestyle Factors:

• Diet-related factors:
  • High glycemic index foods 4, 5
  • Excessive dairy consumption 4, 5
  • Sugary and greasy foods 6
• Medications that can trigger acne:
  • Testosterone
  • Progesterone
  • Corticosteroids
  • Lithium
  • Phenytoin
  • Isoniazid
  • Vitamins B2, B6, and B12
  • Halogens
  • Epidermal growth factor inhibitors 3
• Environmental exposures:
  • Air pollution 6
  • High humidity and temperature 6
  • Sun exposure (can initially improve but later worsen acne) 6
  • Mineral oils and halogenated hydrocarbons (can cause chloracne) 6

Other Contributing Factors:

• Psychological stress: Triggers inflammatory responses and affects hormone levels 7
• Improper use of cosmetics: Especially oil-based products 6
• Electronic device usage: Long-term exposure may affect skin 6
• Poor sleep quality: Disrupts hormonal balance 6
• Obesity: Associated with hormonal imbalances 3, 6

Common Myths About Acne

Myth 1: Poor hygiene causes acne

• Fact: Acne is not caused by dirt or surface skin oils. Excessive washing can actually irritate the skin and worsen acne 1, 4

Myth 2: All foods affect acne equally

• Fact: While diet can influence acne, not all foods have equal impact. High glycemic foods and dairy products have stronger evidence for association than chocolate or greasy foods in general 4, 5

Myth 3: Acne only affects teenagers

• Fact: While acne affects approximately 85% of teenagers, it also affects 42.5% of men and 50.9% of women between ages 20-30, and can persist into adulthood 3, 4

Myth 4: Sun exposure clears acne

• Fact: While initial sun exposure may temporarily improve acne due to anti-inflammatory effects, prolonged exposure can worsen acne and cause skin damage 6

Myth 5: Acne is just cosmetic and not a medical condition

• Fact: Acne is a legitimate inflammatory skin disease with significant physical and psychological impacts, including scarring, depression, anxiety, and reduced quality of life 1, 4

Myth 6: All acne treatments work the same for everyone

• Fact: Treatment response varies based on acne type, severity, and individual factors. What works for one person may not work for another 1, 4

Myth 7: Stress doesn't affect acne

• Fact: Psychological stress can trigger or exacerbate acne through neurogenic factors and hormonal changes 7

Clinical Implications

• Acne severity assessment should be standardized using validated scales like the Investigator Global Assessment (IGA) 1
• For patients with signs of hormonal disorders (irregular menses, hirsutism, etc.), endocrinologic testing may be warranted 1
• Treatment should be tailored to acne severity, with topical therapies for mild cases and combination approaches including systemic medications for moderate to severe cases 4
• Addressing psychological impacts of acne is important, as it can cause significant distress, depression, and anxiety 1, 7, 4

Understanding these causes and dispelling myths helps in developing effective treatment strategies and providing appropriate patient education about this common but impactful skin condition.