Diabetic dermopathy

Diabetic dermopathy also known as shin spots or pigmented pretibial patches, is common skin problem for people with diabetes that is characterized by oval or round, slightly indented scaly patches that are light brown or reddish, often on the front of your legs (the shins) that can turn into ulcers. Although these lesions may appear in anyone, particularly after an injury or trauma to the area, they are one of the most common skin problems found in patients with diabetes mellitus. Any patient with such a rash, if not already diagnosed, should be investigated to exclude diabetes. Diabetic dermopathy tends to occur in older patients with long-standing diabetes. Diabetic dermopathy has been found to occur in up to 30% of patients with diabetes.

Although disputed, some consider the presence of diabetic dermopathy to be pathognomonic for diabetes ¹. Diabetic dermopathy has a strong predilection for men and those older than 50 years of age ². Although diabetic dermopathy may precede the onset of diabetes, it occurs more frequently as a late complication of diabetes and in those with microvascular disease. Nephropathy, neuropathy, and retinopathy are regularly present in patients with diabetic dermopathy. An association with cardiovascular disease has also been identified, with one study showing 53% of non-insulin-dependent diabetes mellitus with diabetic dermopathy had coexisting coronary artery disease ³.

The cause of diabetic dermopathy is unknown but is linked to an increased glycosylated hemoglobin (HbA1c) and poor diabetes control. Diabetes can affect the small blood vessels of your body that supply your skin with blood. Changes to the blood vessels because of diabetes can cause a skin condition called diabetic dermopathy.

Treatment is typically avoided given the asymptomatic and self-resolving nature of diabetic dermopathy especially if better control of the diabetes is achieved, as well as the ineffectiveness of available treatments. However, diabetic dermopathy often occurs in the context of microvascular complications and neuropathies ²; hence, patients need to be examined and followed more rigorously for these complications. Although it is important to manage diabetes and its complications accordingly, there is no evidence that improved glycemic control alters the development of diabetic dermopathy.

Diabetic dermopathy causes

The exact cause of diabetic dermopathy is unknown but may be associated with diabetic neuropathic or destruction of subcutaneous nerves ⁴ and vascular complications ⁵, as studies have shown the condition to occur more frequently in diabetic patients with retinopathy, neuropathy and nephropathy.

Diabetic dermopathy tends to occur in older patients or those who have had diabetes for at least 10–20 years. It also appears to be closely linked to increased glycosylated hemoglobin, an indicator of poor control of blood glucose levels.

Because lesions often occur over bony parts of the body such as the shins, it is thought that diabetic dermopathy may also be a magnified response to injury or trauma to these areas ⁶ and hemosiderin and melanin deposition ⁷. Studies have shown that shin spots have appeared in response to trauma with heat, cold or blunt objects in patients with diabetes.

Diabetic dermopathy symptoms

Diabetic dermopathy lesions appear most frequently on your shins. Less commonly lesions can be found on the front of the thighs, forearm, side of the foot, scalp and trunk. Features of diabetic dermopathy lesions are:

• Round or oval-shaped
• Reddish-brown color
• Initially scaly but then flattens out and becomes indented
• Commonly occur on both shins.

The presence of four or more lesions is almost always limited to patients with diabetes. People presenting with shin spots not already diagnosed with diabetes should undergo a further investigation to rule out the possibility of early diabetes.

Diabetic dermopathy initially presents with rounded, dull, red papules that progressively evolve over one-to-two weeks into well-circumscribed, atrophic, brown macules with a fine scale. Normally after about eighteen to twenty-four months, lesions dissipate and leave behind an area of concavity and hyperpigmentation. At any time, different lesions can present at different stages of evolution. The lesions are normally distributed bilaterally and localized over bony prominences. The pretibial area is most commonly involved, although other bony prominences such as the forearms, lateral malleoli or thighs may also be involved. Aside from the aforementioned changes, patients are otherwise asymptomatic.

Diabetic dermopathy diagnosis

Diabetic dermopathy is a clinical diagnosis that should not require a skin biopsy. Histologically, diabetic dermopathy is rather nonspecific; it is characterized by lymphocytic infiltrates surrounding vasculature, engorged blood vessels in the papillary dermis, and dispersed hemosiderin deposits. Moreover, the histology varies based on the stage of the lesion. Immature lesions present with epidermal edema as opposed to epidermal atrophy which is representative of older lesions ⁸.

Diabetic dermopathy treatment

Diabetic dermopathy patches do not hurt, blister, or itch, and are harmless. Diabetic dermopathy lesions or shin spots usually do not require any treatment and tend to go away after a few years, particularly following improved blood glucose control.

Tips for diabetic skin care

Skin care for people with diabetes is really no different to that which is required by those who don’t have diabetes. However, a few extra skin care tips can help ensure and maintain healthy skin.

• Wash with a mild, neutral soap and make sure that as well as rinsing you also dry yourself. This may include drying between your toes, under your arms, and anywhere else that water can hide.
• Use a moisturizing lotion to keep you skin soft and moist. This type of cream is widely available and can make a huge difference.
• Keeping hydrated can help with keeping your skin moist and healthy.
• Wear loose-fitting underwear made from 100% cotton – this allows a healthy through flow of air.
• Consider wearing special socks and shoes if you have neuropathy and are worried about skin care of your feet.
• Keep a close eye on any dry or red spots on your skin, and be ready to act by ontacting your healthcare professional sooner rather than later.
• Keep an extra close eye on any areas affected by neuropathy and make sure to seek professional advice at an early stage.
• Seek medical advice if you have persistent dry skin as this can lead to infections, which can quickly develop into serious complications.

If your skin problems worsen over time, see a doctor immediately.

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