A 16-year-old boy (Figure 96-1) with severe nodulocystic acne and scarring presents for treatment. After trying oral antibiotics, topical retinoids, and topical benzyl peroxide with no significant benefit, the patient and his mother request isotretinoin (Accutane). After 4 months of isotretinoin, the nodules and cysts cleared, and there remained only a few papules (Figure 96-2). He is much happier and more confident about his appearance. The skin fully cleared after the last month of isotretinoin.

Acne is an obstructive and inflammatory disease of the pilosebaceous unit predominantly found on the face of adolescents. However, it can occur at any age and often involves the trunk in addition to the face.

Acne vulgaris affects more than 80 percent of teenagers, and persists beyond the age of 25 years in 3 percent of men and 12 percent of women.¹

The four most important steps in acne pathogenesis:

1. 
   

   Sebum overproduction related to androgenic hormones and genetics.

   
   
2. 
   

   Abnormal desquamation of the follicular epithelium (keratin plugging).

   
   
3. 
   

   Propionibacterium acnes proliferation.

   
   
4. 
   

   Follicular obstruction, which can lead to inflammation and follicular disruption.

Neonatal acne is thought to be related to maternal hormones and is temporary (Figure 96-3).

Acne can be precipitated by mechanical pressure as with a helmet strap (Figure 96-4) and medications such as phenytoin and lithium (Figure 96-5).

There are some studies that suggest that consumption of large quantities of milk (especially skim milk) increase the risk for acne in teenagers.²

Clinical Features

Morphology of acne includes comedones, papules, pustules, nodules, and cysts.

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  Obstructive acne = comedonal acne = noninflammatory acne and consists of only comedones (Figure 96-6).

  
  
• 
  

  Open comedones are blackheads (Figure 96-7) and closed comedones are called whiteheads and look like small papules.

  
  
• 
  

  Inflammatory acne has papules, pustules, nodules, and cysts in addition to comedones (Figure 96-5).

Typical Distribution

Face, back, chest, and neck.

Laboratory Studies

None unless you suspect androgen excess and/or polycystic ovarian syndrome (PCOS).³ SOR A Obtain testosterone and DHEA-S levels if you suspect androgen excess and/or PCOS.

Consider follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels if you suspect PCOS.

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  Acne conglobata is an uncommon and unusually severe form of acne characterized by multiple comedones, cysts, sinus tracks, and abscesses. The inflammatory lesions and scars can lead to significant disfigurement.⁴ Sinus tracks can form with multiple openings that drain foul-smelling purulent material (Figures 96-8 and 96-9). The comedones and nodules are usually found on the chest, shoulders, back, buttocks, and face. In some cases, acne conglobata is part of a follicular occlusion triad including hidradenitis and dissecting cellulitis of the scalp.

  
  
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  Acne fulminans is characterized by sudden onset ulcerative crusting cystic acne, mostly on the chest and back (Figures 96-10 and 96-11).⁵ Fever, malaise, nausea, arthralgia, myalgia, and weight loss are common. Leukocytosis and elevated erythrocyte sedimentation rate are usually found. There may also be focal osteolytic lesions. The term acne fulminans may also be used in cases of severe aggravation of acne without systemic features.⁵

  
  
• 
  

  Pomade acne is described as acne that is caused or exacerbate by greasy hair products that get on the skin of the forehead. It is more commonly seen in African Americans (Figure 96-12).

  
  
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  Rosacea can resemble acne by having papules and pustules on the face. It is usually seen in older adults with prominent erythema and telangiectasias. Rosacea does not include comedones and may have ocular or nasal manifestations (Chapter 97, Rosacea).

  
  
• 
  

  Folliculitis on the back may be confused with acne. Look for hairs centrally located in the inflammatory papules of folliculitis to help distinguish it from acne. Acne on the back usually accompanies acne on the face as well (Chapter 100, Folliculitis).

  
  
• 
  

  Acne keloidalis nuchae consists of papules, pustules, nodules, and keloidal tissue found at the posterior hairline. It is most often seen in persons of color after shaving the hair at the nape of the neck (Figure 96-13).