How To Recognize Skin Disorders In Diabetic Patients

By Anthony Yung, DPM

Key Insights On Granuloma Annulare
In contrast, granuloma annulare is a relatively common skin disorder and not considered to be a marker for diabetes. Only 21 percent of patients with granuloma annulare have diabetes.5 This skin disorder has striking similarities to NLD and may appear as a generalized or localized disorder. Eighty-five percent of cases are localized. This is a self-limiting process that generally resolves in several years. The average age of onset is 51 years.
Lesions begin as dermal papules and gradually expand into annular borders with central hyperpigmentation. These may appear in the hundreds and may coalesce into annular plaques. The dorsum of the hands and arm are the most common sites with the feet and legs less frequently involved.
The pathophysiology of this disease is unknown. Trauma, infectious processes, genetic disposition, vasculitis and sun exposure have all been suggested as causes without convincing corroborative evidence. Histologically, there is a normal epidermal layer with underlying granulomatous and necrotic upper dermis. These lesions are benign and tend to heal spontaneously without scarring. If you feel treatment is necessary, you may use topical or intralesional steroids.

What About Diabetic Dermopathy And Diabetic Bullae?
Diabetic dermopathy was extensively studied first by Melin in 1964 and was later termed diabetic dermopathy by Binkley one year later.5 Binkley used the term diabetic dermopathy because he believed that the appearance of this entity was diagnostic for diabetes. This is now known to be untrue yet people still use the name. The incidence of this entity is estimated at 30 to 60 percent of diabetic patients with an incidence of 20 percent in non-diabetic patients for age-matched controls.6 The incidence of diabetic dermopathy appears to be greatest in patients with diabetic neuropathy with a male predominance of two to one.7
These lesions are generally asymptomatic and begin as pink patches approximately 0.5-1.0 cm in diameter. Over the next few weeks, these lesions evolve into brown, hyperpigmented, atrophic patches. Individual lesions generally resolve over the course of two years but are continually replaced by new ones. These lesions may heal with or without atrophy and/or hyperpigmentation. They do not require treatment.
The etiology is unknown but is believed to be related to trauma. It was found that diabetic patients with diabetic dermopathy subjected to heat trauma developed additional lesions. However, patients without diabetic dermopathy did not develop lesions.8 Prognosis of lesions is independent of glucose control.
An extremely rare manifestation of longstanding diabetes, diabetic bullae appear in the distal extremeties. Tense blisters form sponatenously without incidence of trauma usually on the feet and shins.9 Blisters are generally non-inflammatory, asymptomatic and rapidly evolving. These blisters generally heal without scarring in several weeks but recurrence may be expected. You may treat bullae topically with local wound care.

Other Pertinent Pointers On Skin Disorders
The findings of thick, tight, waxy skin have been prevalent in diabetics. The thickened, waxy skin limits movement in joints. Up to 50 percent of patients who have had diabetes for 4.5 years or longer were found to have joint limitation.
This is most easily demonstrated by the inability of patients to approximate the palmar surfaces of the proximal and distal interphalangeal joints. This has also been called the “prayer sign.”
The diminished mobility of the skin is related to increased cross-linking and abnormal collagen metabolism. The development of limited joint mobility may lead to an increased risk of microvascular disease as evidenced by nephropathy, retinopathy and neuropathy.10
Yellowing of the palms, soles and face occurs in as many as 10 percent of patients with diabetes. This yellow discoloration is similar to that seen in excess carotene intact. However, this does not seem to be the cause in patients with diabetes. Carotene levels appear normal in the skin of diabetic patients. The cause of this yellow discoloration is unknown. This condition is harmless and never seen in the conjunctiva, thus differentiating this pigmentation from jaundice.

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