Necrobiosis lipoidica diabeticorum (NLD) is a rare skin disease marked by discolored areas that are most often found on the lower legs. It usually affects people who have diabetes or a family history of diabetes. The cause is unclear, though it may be associated with impaired circulation, hyperglycemia, diabetic neuropathy or other complications of diabetes.

NLD may be considered cosmetically unattractive and can be itchy and painful. It is not usually a serious condition, and in some cases the lesions heal without treatment. NLD that causes skin ulcers is a concern for patients with diabetes because diabetes impairs healing, and the lesions can become infected and spread to other tissues.

The appearance of NLD varies, which sometimes complicates distinguishing NLD from other skin conditions, such as diabetic dermopathy. Often it begins as small reddish bumps that enlarge to waxy yellow lesions with a raised red or brown border. It usually appears on the shins but can occur on other parts of the body. Because the lesions described as NLD can vary, a tissue sample (biopsy) may be required for a correct diagnosis.

This condition may be chronic, though many cases do not require treatment. When skin ulcers are present, treatment can help prevent infection. A number of therapies including corticosteroids are available for NLD, but the treatments tend to have mixed success. Prevention may include control of diabetic risk factors.

Necrobiosis lipoidica diabeticorum (NLD) is a skin disease characterized by the destruction of connective and elastic tissue and the development of discolored areas that can cause scarring. The complex name alludes to the various aspects of the condition. Necrobiosis refers to degeneration of collagen, the fibrous protein that provides strength and structure to the skin. Lipoidica refers to lipids (fats) that form in the center of the lesion and give lesions a yellowish color. Diabeticorum refers to the association of NLD with diabetes.

NLD is estimated to affect less than 1 percent of patients with diabetes. It can occur before other signs of the onset of diabetes, such as in the early stages or after years of living with the disease. It also occurs, although less frequently, in people who do not have diabetes or a family history of the disease. When NLD is suspected, patients are advised to undergo screening such as glucose tests to determine whether the lesions are an early indicator of diabetes.

The disease is rare but can occur in nearly anyone. It is found in all races and ethnicities and in both sexes, though women are more likely to develop NLD than men. Lesions tend to start in patients in their 30s, but occurrence of lesions has been recorded at nearly any age.

The disease is difficult to treat and generally chronic. Patients may experience unpredictable periods of inactivity and flare-ups. In some cases, the lesions may heal without any treatment. When the skin lesions do not heal they may lead to complications that could become severe, such as ulcers and infection. The site of lesions should be protected to prevent scratches or other trauma to allow the ulcers to heal.

NLD is sometimes confused with other dermatological disorders. These include:

• Diabetic dermopathy. Scaly brown patches, usually occurring on the shins, due to changes in the small blood vessels caused by diabetes. These harmless patches do not hurt, itch or erupt and do not need treatment.
  
  
• Granuloma annulare. A ring- or arc-shaped rash, usually red or reddish-brown, that can be itchy. It can appear anywhere on the body but usually on areas far from the trunk, such as the hands or ears. The cause is unknown, but people with diabetes are prone to the condition. Treatments include corticosteroid medications and controlled exposure to ultraviolet light.
  
  
• Rheumatoid arthritis nodules. Small lumps that can appear near the joints of the upper and lower limbs of people who have rheumatoid arthritis. Rheumatoid arthritis is a painful, inflammatory autoimmune disease that causes damage to the joints.
  
  
• Eruptive xanthomatosis. Yellow pea-like bumps, each surrounded by a red ring, that appear on the skin in cases of uncontrolled diabetes. Eruptive xanthomatosis can itch and usually occurs on the backs of hands, feet, arms, legs and buttocks. It most frequently occurs in young men with type 1 diabetes who have hyperlipidemia (high levels of fat in the blood).

The cause of necrobiosis lipoidica diabeticorum (NLD) is unknown. A possible source is microangiopathy, which is a type of damage to the small blood vessels that occurs in some patients with diabetes. Hereditary also may be a factor in its development. People with a family history of diabetes appear to have an increased risk of developing NLD.

Several risk factors associated with diabetes make patients more susceptible to NLD and other skin disorders. These include:

• Impaired circulation. Reduced blood flow can damage the skin and other tissues by depriving them of oxygen. This can also suppress the immune system because white blood cells are unable to reach parts of the body.
  
  
• Hyperglycemia. High glucose (blood sugar) causes the body to lose fluid, allowing the skin to dry and crack. It also acts as a fuel for infections and helps infection spread to other parts of the body.
  
  
• Diabetic neuropathy. Autonomic neuropathy (damage to the autonomic nerves controlling involuntary functions) makes the body sweat less. Drier skin is more likely to crack. Peripheral neuropathy (damage to the nerves serving the limbs) impairs sensation and increases the chance of injury and the risk that wounds will go unnoticed and untreated.
  
  
• Hyperlipidemia (high levels of blood fats). High amounts of cholesterol and other fats in the blood can reduce circulation.
  
  
• High blood pressure (hypertension). This can worsen other diabetic risk factors.
  

  

Indicators of necrobiosis lipoidica diabeticorum (NLD) vary widely in patients. The condition usually causes skin lesions to develop on the shins, but lesions can also affect other parts of the legs, arms, hands, trunk, face and scalp. The lesions typically occur on both sides of the body but can also affect just one side.

NLD can spread slowly or rapidly. The patient may feel the need to scratch the sores, but this can cause pain if the sores become opened. The sores may start as one or more small round or oval nodules, often reddish in appearance, which become larger and more irregular lesions. Other common signs and symptoms of NLD include:

• Damage to or wasting of skin
  
  
• Discoloration of the skin. An NLD lesion typically has:
  
  
• A raised border that is purple, dark red or brown
  
  
• A shiny, waxy plaque in the center, made up of fat deposits, that is yellow, yellow-bronze, yellow-pink, orange or, in late stages, brown
  
  
• Destruction of hair follicles
  
  
• Destruction of sebaceous glands, tiny glands in the skin that secrete oil
  
  
• Granulomatous inflammation, containing granular growth (small lumpy lesions)
  
  
• Spider veins (telangiectasia) caused by dilation of small blood vessels underneath the skin’s surface
  
  
• Thickening of the walls of the blood vessels serving the skin

The physician has several ways of diagnosing necrobiosis lipoidica diabeticorum (NLD) and ruling out other skin disorders associated with diabetes that may have similar symptoms. These methods include:

• Medical history. People with diabetes or a family history of the condition are at a higher risk of developing NLD than people with no personal or family history of diabetes.
  
  
• Physical examination. The presence of NLD may be apparent upon visual inspection. The physician will look for the characteristic lesions of the condition, such as yellowish lesions, skin damage and other symptoms.
  
  
• Biopsy. A tissue sample from the lesion may be examined to differentiate NLD lesions from other conditions such as granuloma annulare. A tiny sample may be drawn by a needle or scraped or sliced by a blade. If necessary, a larger sample may be taken in a punch biopsy using a small device to extract the skin sample. A punch biopsy may involve an injection of local anesthesia and stitches after the biopsy, in some cases.
  
  
• Glucose tests. The physician may check the patient’s level of glucose (blood sugar).

Treatment of necrobiosis lipoidica diabeticorum (NLD) with medications may not be necessary. However, medications are typically required if the lesions become ulcers. Treatment at this stage is difficult, especially if the lesions have already ulcerated.

Corticosteroids are typically the first treatment method for NLD. They may be administered in multiple ways. These immunosuppressant anti-inflammatories are likely to be applied as a skin cream (topical) that may be covered with airtight dressings during the early stages of the condition. Many types of topical corticosteroids cannot be used if the lesions have become ulcerated. Instead, the medication may be delivered through an inhaler, injected or taken orally as a pill.

Corticosteroids can cause hyperglycemia (high blood sugar), and long-term use can be a risk factor for diabetes, glaucoma, cataracts, osteoporosis and other conditions. The prescription of corticosteroids would take this effect into account, and some medication types may be considered a treatment of last resort or may not be an option for people with diabetes. If necessary, an individual’s physician can make adjustments in antidiabetic agents or insulin therapy and recommend that the patient perform glucose monitoring more often.

Several common diabetic complications can contribute to NLD, including high blood pressure, unhealthy levels of blood fats (hyperlipidemia), atherosclerosis, poor circulation and diabetic neuropathy. A physician may treat these factors by recommending tighter control of glucose (blood sugar), prescribing medications such as antihypertensives and cholesterol drugs, and suggesting lifestyle changes such as exercise, diet, quitting smoking and wearing compression stockings.

In addition to medications, other therapies that have been used to treat NLD with varying degrees of success. These include:

• Controlled exposure to ultraviolet light to control flare-ups
  
  
• Stockings or shin pads to protect against skin trauma
  
  
• Surgical excision, possibly performed with grafting skin to the site in severe cases of ulceration
  
  
• Psychological counseling to address depression, altered body image, impaired self-esteem and other issues that may result from scarring

Preparing questions in advance can help patients have more meaningful discussions with their physicians regarding their conditions. Patients may wish to ask their doctor the following questions about necrobiosis lipoidica diabeticorum (NLD):

1. Why do you think I have NLD?
   
   
2. Could there be another cause of my symptoms?
   
   
3. What could cause my NLD?
   
   
4. Will the symptoms get worse with time?
   
   
5. Can it spread to others? Is it hereditary?
   
   
6. What are my treatment options? How successful are they?
   
   
7. How long will treatment last?
   
   
8. What is the likelihood of symptoms returning after treatment?
   
   
9. Is there anything I can do to prevent further occurrence?
   
   
10. If I haven’t been diagnosed with diabetes, does the development of NLD mean that I have it or am at risk of developing it? Should I have a glucose test to screen for diabetes?