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10 Sneaky Signs of Diabetes

Symptoms from mood swings to vision problems to skin tags can signal diabetes

spinner image doctor checking a person's blood sugar with a finger stick
Tom Werner / Getty Images

Many Americans are familiar with the hallmark symptoms of type 2 diabetes, such as increased thirst and frequent urination. But doctors say there are several lesser-known signs of the disease, and they sometimes emerge before the typical symptoms.

Becoming familiar with those subtler signs can help you catch the disease early. That’s important because the earlier diabetes is diagnosed, the easier it is to treat and manage, says Mandeep Bajaj, M.D., professor at Baylor College of Medicine and chief of endocrinology at Baylor St. Luke’s Medical Center in Houston.

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More than 37 million people in the United States have diabetes, according to estimates from the Centers for Disease Control and Prevention. Remarkably, 1 in 5 don’t know they have it, the CDC says. What’s more, 96 million U.S. adults have prediabetes, in which blood sugar levels are higher than normal but not high enough to be considered type 2 diabetes. About 8 in 10 of them don’t know they have it.

“All of these undiagnosed people walking around with diabetes are at greater risk of complications,” such as chronic kidney disease, heart disease and stroke, as well as nerve, vision and hearing problems, Bajaj says. Controlling your blood sugar through lifestyle changes, medications or insulin injections can delay or prevent those problems.

A primary care physician can diagnose diabetes with a simple blood test. National guidelines call for patients over age 45 to be screened for type 2 diabetes at least every three years, but experts say you should ask your doctor to test you sooner if you have any signs or symptoms or are at higher risk for developing type 2 diabetes.

In addition to excessive thirst and frequent urination, here are some other indicators of diabetes or prediabetes:

1. Chronic yeast infections

High blood sugar from diabetes impairs the immune system, making it harder for your body to fight off infections.

Chronic vaginal yeast infections are particularly common in women with untreated diabetes because the extra sugar in their blood encourages yeast to grow, says Mark Guido, M.D., an endocrinologist with Novant Health Forsyth Endocrine Consultants in Winston Salem, North Carolina.

Other types of recurrent infections — such as skin, bladder and urinary tract infections — can indicate diabetes.

Bajaj says primary care doctors don’t always think about the link between chronic infections and diabetes. If you have repeat infections, he recommends that you ask to be screened.

2. Blurred vision

If it seems like you need frequent updates to your eyeglass prescription, you may want to get tested for diabetes. When your blood sugar levels change quickly, it can cause the lens of your eyes to get cloudy or swell, creating blurry vision.

“People think they need to change their glasses, but actually it may be a sign of diabetes,” Bajaj says.

If left untreated, diabetes damages blood vessels in the back of the eye and can cause cataracts, glaucoma and blindness.

3. Sexual dysfunction

Erectile dysfunction — when a man can no longer have or keep an erection — is common in men with diabetes.

A 2017 systematic meta-analysis found that about 66 percent of men with type 2 diabetes experienced performance issues, and men with diabetes are about 3.5 times more likely to experience erectile dysfunction compared to men without the disease.


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Other studies show that men and women with poorly managed diabetes report a lower sex drive. Researchers say inflammation caused by diabetes may affect the part of the brain that controls sexual desire, according to the American Diabetes Association. Low levels of testosterone may also play a role.

4. Nausea or constipation

High blood sugar can slow the digestive process, making you feel nauseated, constipated or sick to your stomach, Bajaj says.

“You think you have stomach flu, go to the doctor, get some labs, and it turns out your glucose is super high,” Bajaj says.

A typical gastrointestinal illness usually lasts no more than two or three days. If you have nausea, constipation or vomiting that lasts longer, something else is probably causing the problem, Bajaj says, and a diabetes screen should be part of the doctor’s workup.

5. A cut that is slow to heal

If you get a cut or scrape that seems to take forever to heal, diabetes may be the culprit. The extra sugar in your blood when you’re diabetic slows wound healing, leaving you vulnerable to infection, Guido says.

For that reason, surgeons often require patients to undergo diabetes testing before they have surgery, and that can lead to a diabetes diagnosis, Guido says.

“It’s not uncommon for an older adult who needs knee surgery to end up finding out they have diabetes through the pre-op screening,” he says.

6. Mood changes

If you find you’re more irritable, or your family complains about your mood swings, that can be another indicator of diabetes. Diabetes causes fatigue, which can increase moodiness.

Bajaj recalls the case of a patient whose diabetes was detected after he was referred to human resources at work because of his irritability and impatience with colleagues.

“High glucose affects the brain,” Bajaj says. “Someone with undiagnosed diabetes can’t control their emotions. The interesting thing is, once it’s treated and glucose is controlled, these symptoms improve.”

7. Unexplained weight loss

Losing weight is usually a good thing. However, if you’ve lost a significant amount of weight without making any changes to your diet or fitness routine, diabetes could be the culprit.

When you have diabetes, the sugar your body needs for fuel leaves your body in your urine, so your body begins burning fat and muscle for energy, Guido explains. That can result in quick and dramatic weight loss.

“I have patients come and say, ‘I’ve lost 10 pounds in the last four to six weeks and I’m not on a diet,’ ” Bajaj says.

8. Dark patches of skin

Diabetes can cause the skin in the creases around your neck, armpits or groin to get dark and leathery, Guido says. “It looks like your neck is kind of covered with soot, but it doesn’t wash off,” he says.

Called acanthosis nigricans, those dark patches on your skin are a sign of insulin resistance, Guido says, and they can be an early sign of diabetes.

9. Excess facial hair or acne

Some women with insulin resistance develop thick, coarse hair on their faces because insulin can stimulate cells to produce the male hormones that cause hair growth, Guido says. Those same hormones can cause acne.

The good news, Guido says, is that those symptoms tend to resolve once you get glucose levels under control.

10. Skin tags

Another signal that you may have early diabetes is the development of skin tags, fleshy growths often found on the neck, eyelids, armpits and groin.

Although skin tags are generally harmless, many studies have found an increased risk of diabetes in those who have skin tags. A March 2020 study published in the journal BMC Research Notes found that 59 percent of those with skin tags had diabetes, compared with 13 percent of those without skin tags.

Researchers aren’t entirely clear about the mechanism by which diabetes causes skin tags, but they suspect high levels of insulin are to blame. “Insulin resistance sets off growth factors that causes things to grow and change,” Guido says.

Editor's Note: This story, published April 4, 2022, has been updated with new information.

Video: Early Signs of Type 2 Diabetes

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