What is Necrobiosis Lipoidica?
Necrobiosis lipoidica is a rare skin condition which typically affects the lower legs. It is characterized by shiny red yellow plaques which usually enlarge and persist for years. It is 3 times more common in women than in men. It affects all races and can occur at any age, although most commonly occurring in young adults and those of middle age.
What causes Necrobiosis Lipoidica?
The cause of necrobiosis lipoidica is not yet completely understood. It is often seen in diabetic patients with an incidence of 1 in 300. Patients that develop this skin condition who are not known to be diabetic, will often develop diabetes in the future. It is thought to occur due to damage to the skin as well as changes in the small blood vessels of the skin, caused by excess sugar.
What does Necrobiosis Lipoidica look like?
Necrobiosis lipoidica typically starts as multiple small red slightly raised areas on one or both lower legs. Similar spots may develop on other parts of the body such as the hands, arms, trunk or face. These spots tend to grow slowly over several months and may join up to form large flat irregularly shaped lesions. These larger lesions usually have a well-defined red border with a shiny yellow centre. The skin in the centre is typically very thin with visible blood vessels. These patches may persist for many years.
Figure 1. Necrobiosis lipoidica on the lower leg
Reproduced with permission of Dr Deshan Sebaratnam
What other problems can occur with Necrobiosis Lipoidica?
For most patients, the lesions are painless; however due to the thinness of the skin, minor injury to an established patch can cause painful breakdown of the skin which may be at risk of secondary infection and delayed healing. There have also been rare reported cases of skin cancers developing in chronic lesions of necrobiosis lipoidica and thus if a lump, persistent scab or ulcer develops it is important that it be investigated.
How is Necrobiosis Lipoidica diagnosed?
The diagnosis of necrobiosis lipoidica is usually made by a dermatologist after taking a history and examining the skin. A skin biopsy can be taken to confirm the diagnosis. As the presence of necrobiosis lipoidica can usually indicate an underlying disease process, other tests looking for diseases such as diabetes or insulin resistance may be performed.
How is Necrobiosis Lipoidica treated?
Necrobiosis lipoidica does not always require treatment, especially if the patient is not bothered by it cosmetically and it is not painful or ulcerated. However, if that is not the case, treatment is best started in the early stages of this condition before scarring has developed. Use of topical or injected corticosteroids is the first line of treatment however the response is usually modest. If this fails other therapies include:
- Oral corticosteroids
- Topical tacrolimus
- Aspirin and dipyridamole
- Topical PUVA
Rarely the lesion may heal on its own, however the skin overlying the lesion will be thinner and have permanent pigmentary changes.
Things to avoid
It is very important to avoid injury to the skin in the affected area to reduce the chance of ulceration. Avoiding smoking and optimizing diabetic control will also help reduce the risk of skin ulceration, limit the risk of infection and improve wound healing.
What is the likely outcome of Necrobiosis Lipoidica?
Currently, the likely outcomes of necrobiosis lipoidica are not very satisfactory. Treatment is helpful in stopping the expansion of the patches but does not help heal the existing lesions. It is typically a chronic condition with variable progression and scarring. Patients must be mindful that rarely skin cancer can develop in chronic cases of necrobiosis lipoidica and thus a skin check with your dermatologist is recommended if there are any concerns.
This information has been written by Deshan Sebaratnam and Xin Lin Wong
Last updated 7/12/18