Diabetes: 10 warning signs that can appear on your skin

Diabetes can affect many parts of your body, including your skin. When diabetes affects the skin, it could mean that:

• You have undiagnosed diabetes or pre-diabetes.

• Your treatment for diabetes needs to be adjusted.

It’s time to talk with your doctor if you notice any of these warning signs on your skin.

1. Shin spots

This skin condition is common in people who have diabetes. The medical name for shin spots is diabetic dermopathy. You may also hear people refer to this condition as spotted leg syndrome.

When this condition begins, you usually see round or oval spots, which often develop on the shins. The spots may be brown or reddish brown in color.

Early on, these spots often feel scaly. As they flatten out, they can cause small dents in the skin.

Diabetic dermopathy

Because these spots are often brown and cause no symptoms like itch or pain, many people mistake them for age spots.

Unlike age spots, these spots often start to fade after diabetes is well-controlled, usually within 18 to 24 months. Diabetic dermopathy can also stay on the skin indefinitely.

While these spots are harmless, anyone who develops them and hasn’t been diagnosed with diabetes should be tested.

If you have diabetes, tell your doctor about these spots. Some people who have diabetes and shin spots have a higher risk of developing complications from diabetes like neuropathy, which is nerve damage that can lead to weakness, numbness, and pain.

2. Darker area of skin that feels like velvet

A dark patch (or band) of velvety skin on your neck, armpit, groin, or elsewhere could be a sign of pre-diabetes. The medical name for the condition that causes this velvety skin is acanthosis nigricans.

Acanthosis nigricans on the neck

Often developing on the back of the neck, this condition may be the first sign that someone has diabetes or prediabetes.

3. Hard, thickening skin

If you have diabetes, hard, thick, and swollen-looking skin can develop, even when diabetes is well controlled. The medical name for this condition is scleredema diabeticorum.

Often developing on the upper back, the skin thickens and tightens slowly over months or years. This condition can also occur on the shoulders, neck, or elsewhere, but never on the hands or feet.

Scleredema diabeticorum

Some people have discoloration where the skin is hard and thickening.

While the skin hardens and thickens, the condition is painless.

4. Open sores and wounds

Having high blood sugar (glucose) for a long time can lead to poor circulation and nerve damage. You may have developed these if you’ve had uncontrolled (or poorly controlled) diabetes for a long time.

Poor circulation and nerve damage can make it hard for your body to heal wounds. This is especially true on the feet. The open wounds are called diabetic ulcers.

If you have diabetes, check your feet every day for sores and open wounds

If you see a sore, cut, open wound, swelling, discoloration, or other change, contact your doctor right away.

5. Outbreak of small bumps

Uncontrolled diabetes can cause extremely high levels of triglycerides, a type of fat that circulates in the blood. If this happens, you can develop a skin condition called eruptive xanthomatosis.

Eruptive xanthomatosis

If you have undiagnosed diabetes or diabetes that is not well controlled, these bumps can appear on your skin suddenly.

After the bumps appear, they soon develop a yellowish color in lighter skin tones. If you have a darker skin tone, you may see a grayish color with a yellowish hue beneath. You’ll usually find these bumps on the buttocks, thighs, crooks of the elbows, or knees. They can form anywhere though. No matter where they form, they are usually tender and itchy.

Once the diabetes is well-controlled, the bumps tend to go away.

6. Yellowish, smooth bumps or patch(es) on and around your eyelids

These bumps and patches develop when you have high levels of fat in your blood, which can be a sign that you have poorly controlled diabetes. The medical name for this condition is xanthelasma.

Regardless of your skin tone, these bumps and patches look yellowish or yellowish orange in color.

Xanthelasma

The yellowish bumps and patches usually appear in about the same place on (or around) both eyelids. These bumps and patches can feel soft or somewhat hard.

7. Infections

Diabetes weakens your immune system, which reduces your body’s ability to fight off harmful germs and increases your risk of developing infections. It's common to develop infections in the mouth like oral thrush or in the vagina like a yeast infection.

Do you get several yeast infections each year?

Ask your doctor if you might have diabetes or pre-diabetes.

8. Skin tags

Many people have skin tags, which are harmless growths that can appear anywhere on the skin. Sometimes, skin tags are firmly fixed to the skin. You may also see ones that dangle from a stalk. The medical name for these growths is acrochordons.

While skin tags can develop anywhere on the skin, they are most common on the eyelids, neck, armpit, and groin.

Skin tags

While harmless, having many skin tags may be a sign that you have type 2 diabetes.

9. Cluster of small bumps or a raised patch

Whether this skin condition is associated with diabetes is controversial. We know that most people who have granuloma annulare do not have diabetes.

Several studies, however, have found this skin condition in patients who have diabetes. One such study found that people with diabetes were most likely to have granuloma annulare over large areas of skin and that the bumps came and went. Another study concluded that people who have granuloma annulare that comes and goes should be tested for diabetes.

Granuloma annulare

This skin condition causes bumps and patches that may be skin colored, red, pink, or bluish purple.

10. Yellow, reddish, brown, or purplish patches on your skin

When this condition begins, you’ll often see one or a few reddish-brown spots on your shins if you have a lighter skin tone. People with darker skin tones often see purplish spots. These spots aren’t itchy or painful. The medical name for this condition is necrobiosis lipoidica.

These spots grow slowly, becoming one or more patches that may be yellow, reddish, brown, or purplish. In the center, you may see waxy skin that is thinning, blood vessels, or both.

Necrobiosis lipoidica on a person’s shins

The lighter areas in the reddish patches are waxy-feeling skin.

When to see a dermatologist

Diabetes can cause skin problems. Most of these skin problems are harmless, but even a minor one can become serious if you have diabetes. A board-certified dermatologist can recognize skin problems due to diabetes and help you manage them.

Are all dermatologists board certified?

No. See what it takes to become board certified.

What is a dermatologist?

Images

• Images 1, 2, 6, 8, 9, 11, 12, 13, 14: Reproduced with permission from ©DermNet www.dermnetnz.org 2023.

• Image 3, 4: Used with permission of the Journal of the American Academy of Dermatology:

  • J Am Acad Dermatol 2007;57:502-8.

  • J Am Acad Dermatol 2014;71:e99-e101.

• Images 5, 10: Getty Images

• Image 7: Used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.

References
Centers for Disease Control and Prevention. “Diabetes and your feet.” Last updated 4/11/2023. Last accessed 11/28/2023.

Cohen Sabban, EN. “Cutaneous manifestations of diabetes mellitus from A to Z.” Focus session presented at: 74th Annual Meeting of the American Academy of Dermatology; March 4-8, 2016; Washington D.C.

Duff M, Demidova O, et al. “Cutaneous manifestations of diabetes mellitus.” Clinical Diabetes. 2015;33:40-8.Lima AL, Illing T, et al. “Cutaneous manifestations of diabetes mellitus: A review.” Am J Clin Dermatol. 2017 Aug;18(4):541-53. 

Martín C, Requena L, et al. “Scleredema diabeticorum in a patient with type 2 diabetes mellitus.” Case Rep Endocrinol. 2011;2011:560273. 

McKinley-Grant L, Dronavalli S, et al. “Cutaneous manifestations of systemic disease.” In: Taylor and Kelly’s Dermatology for Skin of Color. (second edition). McGraw Hill, USA, 2016:479-85.

Morgan AJ and Schwartz RA. “Diabetic dermopathy: A subtle sign with grave implications.” J Am Acad Dermatol. 2008;58:447-51.

Pereira M, Pinheiro RR, et al. “Scleredema diabeticorum.” Dermatol Reports. 2022 Nov 21;14(4):9477.

Vangara SS, Klingbeil KD, et al. “Severe hypertriglyceridemia presenting as eruptive xanthomatosis.” J Family Med Prim Care. 2018 Jan-Feb;7(1):267-70.

Written by:
Paula Ludmann, MS

Reviewed by:
Brendan Camp, MD, FAAD
Amanda Friedrichs, MD, FAAD
William D. James, MD, FAAD
Omolara Olowoyeye, MD, FAAD

Last updated: 5/22/24