People with diabetes are more likely to have skin problems, including dark spots on your legs and other areas. Sometimes these spots are harmless, but other times, they may signal poor blood glucose (sugar) control or an infection. Here’s what you should know about these skin issues and when to talk with your doctor.

Diabetic Dermopathy

If you notice dark patches on your shins, you might have diabetic dermopathy — also called shin spots or spotted leg syndrome. Up to 50 percent of all people with diabetes get this condition, which develops when tiny blood vessels don’t bring enough blood to the skin. This can be caused by:

• Poor circulation
• Iron or pigment buildup
• Mild bruising
• Nerve damage

Shin spots usually start as dull, dark or reddish circles over the bony part of the lower legs or forearms. These gradually turn into brown, scaly patches that range from about a third of an inch to an inch wide — about the size of a pea to a quarter. They usually don’t hurt or itch, and people often mistake them for age spots. After 18 to 24 months, the patches may fade, sometimes leaving small indents or discoloration.

There’s no specific treatment for diabetic dermopathy, but it may improve with tighter blood sugar control. The spots themselves aren’t dangerous, but they could mean you’re at higher risk of other diabetes complications such as neuropathy (nerve damage).

It’s worth bringing shin spots to your doctor’s attention. If a dermatologist (skin specialist) confirms the diagnosis and rules out other problems, you can consider using makeup to cover the spots.

Dark Patches on the Skin

Some people with diabetes develop larger dark patches due to certain skin conditions. For example, necrobiosis lipoidica causes raised, slow-growing patches, usually on the shins. These areas may be red, brown, yellow, or purplish, depending on your natural skin color, and they may look waxy or shiny and lighter in the center. This condition is rare but tends to affect women, according to the American Diabetes Association.

Necrobiosis lipoidica can last a long time and become painful and itchy, sometimes causing scars that may be disfiguring. In severe cases, the patches can crack open, raising the risk of infection. If you notice any of these changes, talk to your doctor. Treatment may include steroid creams to reduce inflammation.

Another skin condition linked to diabetes is acanthosis nigricans, which causes dark patches that feel thick or velvety. These symptoms often show up on the back of the neck but can also appear in other parts of the body, like the knees.

Acanthosis nigricans can be an early warning of prediabetes or insulin resistance (when your body has trouble using insulin properly). Getting more physical activity and maintaining a healthy weight can help improve insulin sensitivity and reduce these skin changes.

Diabetic Ulcers and Infections

Dark spots on your legs and feet can sometimes be signs of something more serious — like a wound or infection. High blood sugar can damage nerves and blood vessels, making it harder for your body to heal even small cuts. You might not worry if you nick yourself while shaving or stub your toe, but if a minor injury doesn’t heal, it can turn into an open sore or become infected.

These open wounds are called diabetic ulcers, and they need special care. It’s important to check your legs and feet regularly for any cuts, blisters, or spots that don’t look right. Let your doctor or diabetes care team know if you notice anything unusual. They can help you take steps to promote better healing and prevent infections.

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Skin infections may be caused by bacteria, fungi, or a virus. One common bacterial infection, folliculitis, develops when hair follicles (the tiny openings where hairs grow) become infected, often from shaving or sweating. The area may look red or dark and feel swollen or painful. Folliculitis usually clears up with antibiotics.

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Fungal infections are usually caused by a type of yeast that grows in warm, damp places on your body, such as skin folds and moist, sweaty areas — like the armpits or back of the knee. Symptoms such as itchy rashes, small blisters, or scaly patches are more likely to show up if your blood sugar is high, which makes it harder for your body to fight off germs.

Skin Care for Diabetes

Dark spots aren’t necessarily a cause for alarm. But if you’re living with diabetes, it’s important to take extra precautions when caring for your skin and watch for changes in how it looks or feels. Protecting your skin from injuries may help reduce the risk of diabetic dermopathy and other causes of dark spots. If you play sports or do activities where your legs might get bumped or scraped, consider wearing knee or shin guards.

Good skin care starts from the inside out. Maintaining good control of your blood sugar is the first step to keeping your skin healthy. High blood sugar can lead to dry skin and itchiness, and scratching could make you prone to inflammation, rashes, scarring, or even infections.

In addition, poor circulation related to diabetes can cause itchiness, especially on the lower legs. This can be a sign of long-term damage from high blood sugar. Talk with your doctor or endocrinologist to learn how to get better control of your condition. Your healthcare provider might suggest adjusting your treatment plan or suggest meeting with a dietitian to review your eating habits and make changes that support skin and blood sugar health.

To care for your skin:

• Wash with gentle soap and warm water.
• Moisturize with lotion if your skin feels dry or tight.
• Check your skin regularly, especially on your feet and lower legs.
• Let your doctor know right away if you have a cut, burn, or sore that isn’t healing.

Skin infections that used to be dangerous for people with diabetes can now be treated with antibiotics and other medical care. Getting help at the first sign of a problem gives you the best chance of a smooth recovery.

Talk With Others Who Understand

DiabetesTeam is the social network for people with diabetes mellitus and their loved ones. On DiabetesTeam, members come together to ask questions, give advice, and share their stories with others who understand life with diabetes.

Have you noticed brown patches or skin lesions on your legs since getting diagnosed with diabetes? If so, what treatment options have helped you? Share your comments below, or start a conversation by posting on your Activities page.