A 40-year-old woman with a history of diabetes presents with red plaques on her shins (Figures 95-1 and 95-2). They are asymptomatic, though continue to increase in size. A biopsy was previously taken and revealed necrobiosis lipoidica. She had been working closely with her primary care physician to better control her glucose, but the lesions continued to progress. She has been applying topical corticosteroids with minimal improvement. This story demonstrates a typical case of necrobiosis lipoidica refractory to treatment in spite of well-controlled diabetes.

Necrobiosis Lipoidica

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  Strongly associated with diabetes mellitus (usually type 1), though rarely may occur in patients who are not diabetic.¹

  
  
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  Percentage of patients with diabetes at the time of presentation ranges from 11% to 65%.¹

  
  
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  Patients without diabetes on presentation may have impaired glucose tolerance, develop diabetes at a later date, or have positive family histories of diabetes.¹

  
  
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  May occur at any age, though tends to develop at an earlier age in patients with pre-existing diabetes.²

  
  
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  Women are affected three times as often as men.¹

Diabetic Dermopathy

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  Most common cutaneous finding in patients with diabetes mellitus, occurring in 9% to 55% of diabetics.³

  
  
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  Incidence increased in diabetics with other microangiopathic complications of diabetes (retinal, neuropathic, and/or nephrogenic).³

  
  
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  Occurs in both insulin-dependent and noninsulin-dependent diabetics.²

  
  
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  Incidence increases with age, typically seen in patients older than 50 years.³

  
  
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  Men are affected more often than women.⁴

Necrobiosis Lipoidica

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  Disorder of collagen degeneration with granuloma formation and fat deposition.¹

  
  
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  Etiology remains unknown; however, it may be related to immunologically mediated vascular disease, diabetic microangiopathy, or defective collagen.¹

Diabetic Dermopathy

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  Etiology largely unknown; however, trauma may be a causative factor.³

  
  
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  Previously thought to be related to ischemia, though lesions are now recognized to have more blood flow than surrounding skin.⁵

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  Necrobiosis lipoidica—A biopsy is typically performed for diagnosis. No further laboratory workup is helpful in making a diagnosis.¹

  
  
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  Diabetic dermopathy—This is a clinical diagnosis with no laboratory workup or biopsy necessary.³

Clinical Features

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  Necrobiosis lipoidica—characterized by asymptomatic shiny, red-brown, telangiectatic papules, patches, plaques, or nodules (Figures 95-1 and 95-2).¹ Koebnerization may be involved in new lesion formation. Over time, the lesions enlarge and coalesce, often becoming waxy and atrophic centrally (Figure 95-3). Painful ulcers occur at sites of trauma in 35% of lesions (Figures 95-3 and 95-4).¹

  
  
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  Diabetic dermopathy—characterized by asymptomatic reddish-brown macules, patches, and papules (Figures 95-5,95-6,95-7). They are usually oval, round, or linear in shape, clearly demarcated from surrounding skin. Older lesions may be covered with a thin scale and may appear atrophic and hyperpigmented. Individual lesions may resolve completely over a period of 18 to 24 months; however, new lesions continuously form.³