Acne

• Definition
• Clinical Features
• Acne Variants
  
• Childhood acne
• "Follicular Occlusion Triad"
• Acne fulminans
• Acne excoriée
• Pathogenesis
  
• Evolution of Acne
  
• Common Misconceptions
  
• Diagnosis and Differential Diagnosis (see Table)
  

Acne

Comedonal Acne

Cystic Acne

Pustular Acne

Acne Pustule

Mild Papular Acne

Acne keloids

Acne Scars

• Definition:  a chronic inflammatory disorder of the pilosebaceous unit.  The presence of a "comedone" (follicular plug) is essential for the diagnosis.
  

• Clinical Features:
  
  • Acne vulgaris and its variants do not exist in the absence of comedones (see pathogenesis).
    
    
  • A comedone is a plug that occurs in the follicle (pore) and these are visible either as black dots (blackheads) or small white papules (whiteheads).
    
    
  • The black in the blackheads was originally thought to be due to melanin but this is no longer obviously correct and the origin is uncertain. It is not dirt.
    
    
  • Comedones can generally be safely removed with the gentle application of a "comedone extractor", and this may be a useful maneuver in diagnosis.
    
    
  • Variation of the associated inflammatory response determines the variety of the lesions found in acne. These vary from papules and pustules at the milder end of the inflammatory spectrum to deep seated nodules, cysts and connecting sinuses at the more severe end.
    
    
  • Some lesions may show evidence for scratching (excoriation) and crust formation which also indicates manipulation by the patient.
    
    
  • The distribution of acne corresponds to the distribution of the so-called "sebaceous follicles"; that is, hair follicles having very large sebaceous glands and small hairs. These are characteristically found on the face, chest and back.
    
    
  • Individual patients, however, tend to have their own patterns of involvement in one or more of the three areas, and within areas, there may also be selective involvement such as the forehead, the jaw line or the presternal skin.
    
    
  • Comedones develop slowly and persist for long periods of time (on the order of months), whereas inflammation is more variable. Persistent inflammation leads to scarring.
    
    
• More Images:
  

  Closed Comedones	Open Comedones
  Acne Nodules	Acne Cysts