Diabetes warning signs

Diabetes can affect many parts of your body, including your skin. When diabetes affects the skin, it’s often a sign that your blood sugar (glucose) levels are too high. This could mean that:

  • You have undiagnosed diabetes, or pre-diabetes
  • Your treatment for diabetes needs to be adjusted

If you notice any of the following warning signs on your skin, it’s time to talk with your doctor.

Necrobiosis lipoidica: When this woman saw a dermatologist about these red, swollen, and hard patches on her legs, she learned she had diabetes.

1. Yellow, reddish, or brown patches on your skin

This skin condition often begins as small raised solid bumps that look like pimples. As it progresses, these bumps turn into patches of swollen and hard skin. The patches can be yellow, reddish, or brown. You may also notice:

  • The surrounding skin has a shiny porcelain-like appearance
  • You can see blood vessels
  • The skin is itchy and painful
  • The skin disease goes through cycles where it is active, inactive, and then active again

The medical name for this condition is necrobiosis lipodica (neck-row-by-oh-sis lee-poi-dee-ka).


  • Get tested for diabetes if you have not been diagnosed.
  • Work with your doctor to better control your diabetes.
  • See a dermatologist about your skin. Necorbiosis lipodica is harmless, but it can lead to complications.

Acanthosis nigricans (AN): Often causing darker skin in the creases of the neck, AN may be the first sign that someone has diabetes.

2. Darker area of skin that feels like velvet

A dark patch (or band) of velvety skin on the back of your neck, armpit, groin, or elsewhere could mean that you have too much insulin in your blood. AN is often a sign of prediabetes. The medical name for this skin condition is acanthosis nigricans (ay-can-THOE-sis NIE-gri-cans).

TAKE ACTION : Get tested for diabetes.

3. Hard, thickening skin

When this develops on the fingers, toes, or both, the medical name for this condition is digital sclerosis (sclear-row-sis).

On the hands, you’ll notice tight, waxy skin on the backs of your hands. The fingers can become stiff and difficult to move. If diabetes has been poorly controlled for years, it can feel like you have pebbles in your fingertips.

Hard, thick, and swollen-looking skin can spread, appearing on the forearms and upper arms. It can also develop on the upper back, shoulders, and neck. Sometimes, the thickening skin spreads to the face, shoulders, and chest.

In rare cases, the skin over the knees, ankles, or elbows also thickens, making it difficult to straighten your leg, point your foot, or bend your arm. Wherever it appears, the thickened skin often has the texture of an orange peel.

This skin problem usually develops in people who have complications due to diabetes or diabetes that is difficult to treat.


  • Tell your doctor about the thickening skin. Getting better control of your diabetes can bring relief.
  • You may also need physical therapy. When the thickening skin develops on a finger, toe, or other area with joints, physical therapy can help you keep your ability to bend and straighten the joint.

Blister: Large blisters like this one can form on the skin of people who have diabetes.

4. Blisters

It’s rare, but people with diabetes can see blisters suddenly appear on their skin. You may see a large blister, a group of blisters, or both. The blisters tend to form on the hands, feet, legs, or forearms and look like the blisters that appear after a serious burn. Unlike the blisters that develop after a burn, these blisters are not painful.

The medical name for this condition is bullosis (bull-low-sis) diabetricorum . Sometimes, it’s called diabetic bullae (bull-lie).


  • Tell your doctor about the blisters. You’ll want to take steps to prevent an infection.
  • Talk with your doctor about how to better control your diabetes.

Has it been a year or longer since your last period, and do you get several yeast infections each year? It’s possible that you have diabetes or pre-diabetes.

5. Skin infections

People who have diabetes tend to get skin infections. If you have a skin infection, you’ll notice one or more of the following:

  • Hot, swollen skin that is painful
  • An itchy rash and sometimes tiny blisters, dry scaly skin, or a white discharge that looks like cottage cheese

A skin infection can occur on any area of your body, including between your toes, around one or more of your nails, and on your scalp.


  • Get immediate treatment for the infection.
  • Tell your doctor if you have frequent skin infections. You could have undiagnosed diabetes.
  • If you’ve been diagnosed with diabetes, you may need better control of it.

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

6. 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. These open wounds are called diabetic ulcers .


  • Get immediate medical care for an open sore or wound.
  • Work with your doctor to better control your diabetes.

Diabetic dermopathy: This 55-year-old man has had diabetes for many years.

7. Shin spots

This skin condition causes spots (and sometimes lines) that create a barely noticeable depression in the skin. It’s common in people who have diabetes. The medical name is diabetic dermopathy (der-mop-ah-thē). It usually forms on the shins. In rare cases, you’ll see it on the arms, thighs, trunk, or other areas of the body.

The spots are often brown and cause no symptoms. For these reasons, many people mistake them for age spots. Unlike age spots, these spots and lines usually start to fade after 18 to 24 months. Diabetic dermopathy can also stay on the skin indefinitely.


  • Tell your doctor about these spots.
  • Work with your doctor to better control your diabetes.
  • If you haven’t been diagnosed with diabetes, get tested.

Eruptive xanthomatosis: These bumps appear suddenly and clear promptly when diabetes is well-controlled.

8. Outbreak of small, reddish-yellow bumps

When these bumps appear, they often look like pimples. Unlike pimples, they soon develop a yellowish color. You’ll usually find these bumps on the buttocks, thighs, crooks of the elbows, or backs of the knees. They can form anywhere though.

No matter where they form, they are usually tender and itchy. The medical name for this skin condition is eruptive xanthomatosis (zan-tho-ma-toe-sis).


  • Tell your doctor about the bumps because this skin condition appears when you have uncontrolled diabetes.
  • Talk with your doctor about how to better control your diabetes.

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

9. Red or skin-colored raised bumps

Whether this skin condition is associated with diabetes is controversial. We know that most people who have granuloma annulare (gran-you-low-ma ann-you-lar-ē) 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.


  • Let your doctor know if you have bumps like those shown above, especially if the bumps come and go.

10. Extremely, dry itchy skin

If you have diabetes, you’re more likely to have dry skin. High blood sugar (glucose) can cause this. If you have a skin infection or poor circulation, these could also contribute to dry, itchy skin.


  • Tell your doctor about your extremely dry skin. Gaining better control of diabetes can reduce dryness.
  • If you continue to have dry skin after you gain better control of your diabetes, a dermatologist can help.

11. Yellowish scaly patches on and around your eyelids

These develop when you have high fat levels in your blood. It can also be a sign that your diabetes is poorly controlled. The medical name for this condition is xanthelasma (zan-thē-las-ma).


  • Tell your doctor about the yellowish scaly patches around your eyes.
  • Talk with your doctor about how to better control your diabetes. Controlling diabetes can clear the scaly patches.

When to see a dermatologist

Diabetes can cause many other skin problems. Most skin problems are harmless, but even a minor one can become serious in people who have diabetes. A dermatologist can recognize skin problems due to diabetes and help you manage them.

Images 1, 3, 7, 8, 9: Used with permission of the American Academy of Dermatology National Library of Dermatologic Teaching Slides.
Images used with permission of Journal of the American Academy of Dermatology:
2. J Am Acad Dermatol. 2007; 57:502-8
6. J Am Acad Dermatol. 2008; 58:447-51.
Images 4 and 5: Thinkstock

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 DC.
Duff M, Demidova O, et al . “Cutaneous manifestations of diabetes mellitus.” Clinical Diabetes . 2015;33:40-8.
Kalus AA, Chien AJ, et al . “Diabetes mellitus and other endocrine disorders.” In: Wolff K, Goldsmith LA, et al. Fitzpatrick’s Dermatology in General Medicine (seventh edition). McGraw Hill Medical, New York, 2008:1461-70.
McKinley-Grant L, Warnick M, et al . “Cutaneous manifestations of systemic disease.” In: Kelly AP and Taylor S. Dermatology for Skin of Color . (first edition). The McGraw-Hill Companies, Inc. China, 2009:481-4.
Morgan AJ and Schwartz RA. “Diabetic dermopathy: A subtle sign with grave implications.” J Am Acad Dermatol . 2008;58:447-51.
Yosipovitch G, Loh KC, et al . “Medical pearl: Scleroderma-like skin changes in patients with diabetes mellitus.” J Am Acad Dermatol . 2003;48:109-11.

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