Overview
Acne vulgaris is a chronic inflammatory skin condition involving the pilosebaceous unit. It is characterized by the formation of comedones, papules, pustules, nodules, and cysts, primarily occurring in areas with high sebaceous gland density such as the face, back, and chest.
Etiology & Causes
Etiology is multifactorial, involving hyperkeratinization of the follicular epithelium, increased sebum production, colonization by Cutibacterium acnes, and host inflammatory responses. Genetic predisposition plays a significant role, as does hormonal fluctuation.
Pathophysiology
The process begins with microcomedo formation caused by abnormal desquamation of follicular keratinocytes. Increased androgen-driven sebum production promotes C. acnes proliferation. This triggers a proinflammatory cascade, recruiting neutrophils and lymphocytes, leading to the disruption of the follicular wall and subsequent inflammatory lesions.
Epidemiology & Prevalence
Acne affects approximately 80–85% of adolescents and young adults. While peak incidence occurs in puberty, it persists into adulthood in significant proportions of the population, particularly women.
Risk Factors
Genetic susceptibility, hormonal fluctuations (puberty, menstrual cycle), stress, comedogenic cosmetics, and certain dietary factors (high-glycemic index foods).
Symptoms & Warning Signs
A. Early Symptoms
- Microcomedones
- Increased skin oiliness B. Common Symptoms
- Open comedones (blackheads)
- Closed comedones (whiteheads)
- Inflammatory papules C. Advanced Symptoms
- Pustules
- Nodules
- Deep-seated painful cysts D. Emergency Symptoms
- Fulminant acne (sudden onset with systemic symptoms like fever/arthralgia)
Physical Examination Findings
Inspection reveals varying degrees of polymorphic lesions. Palpation may reveal induration (nodules) or fluctuation (abscesses). Scarring or post-inflammatory hyperpigmentation may be evident.
Diagnostic Evaluation
A. Clinical Assessment: Primarily visual diagnosis.
B. Laboratory Testing: Generally unnecessary unless hyperandrogenism is suspected.
C. Imaging Studies: Rare; ultrasound may evaluate cystic depth.
D. Functional Tests: Not applicable.
E. Biopsy Findings: Generally not indicated.
F. Genetic Testing: Not standard.
G. Differential Diagnosis: Rosacea, folliculitis, perioral dermatitis.
Laboratory Tests & Diagnostics
Test Name: Free and Total Testosterone
Type: Blood Test
Purpose: Assess for androgen excess
Expected Findings: Elevated levels
Interpretation: Suggests PCOS or endocrine disorders