How To Recognize Skin Disorders In Diabetic Patients

By Anthony Yung, DPM

At least 30 percent of patients with diabetes will develop cutaneous manifestations in their lifetime.1 Given that diabetes is a systemic disease, its effects on the skin may arise from many different sources (vascular, metabolic, nutritional disturbances, infectious agents and medications). Several common skin disorders may be associated with diabetes. These include necrobiosis lipoidica diabeticorum, granuloma annulare, diabetic bullae, diabetic dermopathy, limited joint mobility and yellow skin phenomenon.
While the exact causes of most pathologic skin changes are unknown, a majority of the skin changes associated with diabetes are related to similar skin changes found with microvascular disorders.

Taking A Closer Look At Necrobiosis Lipoidica Diabeticorum
Necrobiosis lipoidica diabeticorum (NLD) is probably the most well known of skin disorders strongly associated with diabetes mellitus. Muller and his colleagues at the Mayo Clinic found frank diabetes, related biochemical changes, glucose intolerance or positive family history in 90 percent of presenting cases.1 In 15 percent of those cases, the appearance of NLD preceded the diagnosis of diabetes by one to five years. When you see NLD, you should suspect underlying diabetes.
NLD is a rare condition that manifests in only 0.3 percent of the diabetic patient population although it affects females four times as much as males. Also keep in mind that NLD appears earlier in life (30 years) in the diabetic population than in the non-diabetic population (41 years).2
Early presentation of NLD varies from erythematous to violaceous papules or plaques with or without scaling. As the lesions progress, they become increasingly atrophic and assume the characteristic atrophic, waxy, yellow, telangiectatic appearance. These lesions are commonly multiple, bilateral and almost involve the pretibial regions of the lower extremity in 85 percent of the cases. You may also see these lesions on the scalp, arms, trunk, and face. Be aware that common differential diagnoses include: Granuloma annulare, rheumatoid nodule and sarcoidosis.
Light microscopy studies have implicated microvascular disease as an underlying etiology for NLD lesions. However, in up to 30 percent of cases, there is no evidence of vascular disease and researchers have proposed numerous other etiologies including immunopathy, dyslipidemia, abnormal collagen function and vasculopathy. No one mechanism has been satisfactory, although trauma does seem to play a role.2
Typically, one third of lesions ulcerate and only 10 to 20 percent resolve after 10 years.3 Most lesions evolve into the classic atrophic, waxy, yellow lesions that are predisposed to ulceration. Up to 30 percent of these progress on to ischemia, gangrene and ultimately ulceration incited by minor trauma or tissue stress.

Treatment Tips For NLD
No correlation has been found between progression of NLD lesions and glucose control. You may treat early raised lesions with injectible steroids into the advancing border. When it comes to older flat lesions, you should use topical steroids. Recently, researchers have reported some success in using anti-platelet therapy, but the potential role of this therapy awaits further studies.4
It’s important to protect the pretibial areas from trauma in order to prevent ulceration of these sensitive lesions. If the lesions have ulcerated, you should treat them with appropriate wound care therapy including local debridement, topical or systemic antibiosis and grafts when indicated.

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