Would you be able to spot the signs of diabetes?

Diabetes symptoms tend to fly under the radar — which is a reason why an estimated one in five people with diabetes have no idea that they have it. "For many, by the time you start getting symptoms, your diabetes has been around for months or even years," says Dr. Shabina Ahmed, M.D., an endocrinologist and an assistant professor of medicine at Johns Hopkins University, in Baltimore. That said, there may be certain signs that can clue you in that something is going on with your blood sugar. And earlier diagnosis can mean an earlier start to treatment — and a lower risk for the potential for serious side effects.

What is diabetes?

Affecting 38.4 million people in the U.S., diabetes mellitus (the formal name) is a chronic disease caused by too much glucose, or blood sugar, circulating in your body. This results when there’s an imbalance between the body’s demand for insulin (a hormone that regulates blood sugar) and its ability to make enough. See, insulin’s job is to carry glucose to your cells for energy. When it doesn’t, you wind up with too much glucose in your blood, triggering inflammation and ultimately organ damage.

Diabetes has been categorized in many types, but the most commonly known are:

• Type 1 diabetes: This is an autoimmune condition that damages the pancreas to the point where it can’t produce enough insulin.
• Type 2 diabetes: By far the most common type, this is when your pancreas may produce a lot of insulin, but it’s not enough to meet the demand.
• Gestational diabetes: This occurs temporarily during pregnancy and, as with type 2, your body can’t use its insulin supply properly.
• Prediabetes: Rather than a type of diabetes, this is a precursor. Blood sugar levels are elevated, but not high enough to qualify as diabetes.

What are the common signs of diabetes?

While prediabetes is almost always symptom-less (and many patients with diabetes may not have symptoms either), there are some clues that you might have type 1 or type 2 diabetes. These include:

• Frequent urination: With diabetes, your kidneys go into overdrive trying to get rid of the excess glucose, so you end up making a lot more trips to the bathroom. "When your blood sugar levels are consistently elevated above around 180 to 200 mg/dL (milligrams per deciliter), your body starts transferring glucose into the urine," says Dr. Joshua D. Miller, M.D., the founding medical director of Stony Brook University Diabetes Program and an associate professor of endocrinology and metabolism at Stony Brook University, in New York. "The glucose brings water with it, and you have to pee out all that water.” This is often an early sign in children who have type 1 diabetes, especially if they used to stay dry at night and are suddenly soaking their diapers or wetting the bed, says Miller.

• Excessive thirst: This isn’t a simple craving for water. Known as polydipsia, it's more of an unquenchable thirst. "As you become more dehydrated from the frequent urination, your sodium levels go up and the thirst mechanism kicks in," says Miller. The hypothalamus (the part of your brain that regulates thirst) tells your body to crave as much fluid as possible so that it can replace the water your kidneys are using to flush out the glucose. The result: You drink and drink (and drink) but never feel hydrated.

• Increased hunger: When your body can't convert glucose into energy, your body signals to your brain that you should be hungry. Really hungry. This is known as polyphagia.

• Extreme fatigue: Not enough energy in your cells can leave you feeling pretty sluggish and lethargic. (And dehydration can make that even worse.) A study found that 68% of people with type 2 diabetes experienced fatigue. (And it can happen with type 1 too.)

• Tingling, pain, or numbness in the hands or feet: Also known as diabetic neuropathy, these symptoms occur when high blood sugar damages the nerves that send signals to the hands and feet. Most people notice this in the feet first and then in the hands as the disease progresses, says Ahmed. Over time, this nerve damage leads to a reduced sensation of pain. So you could stub your toe (hard!) and not feel a thing.

• Wounds that won't heal: Research shows that the inflammation brought on by uncontrolled diabetes impacts your body’s natural healing process by slowing down blood circulation and the delivery of wound-healing nutrients. As a result, sores and cuts take an extra-long time to heal. "This is a symptom I tend to see most," says Barbra Sassower, RDN, a registered dietitian nutritionist and certified diabetes educator. "Patients don't know they have diabetes, but they have a foot wound that won't go away.”

• Unexplained weight loss: When your body doesn't get the energy it needs from glucose, it turns to fat and muscle instead, resulting in weight loss. This is more common with type 1 diabetes, but can occur with type 2 as well.

• Acanthosis nigricans (AN): A dark patch appearing on the skin with a velvety texture (especially on the neck, armpits, or groin), AN is an indicator of insulin resistance. "This sign usually comes before a type 2 diabetes diagnosis," Ahmed says.

What are the more unusual symptoms of diabetes?

While they aren’t as common as the symptoms listed above, doctors do sometimes see the following in people with diabetes.

• Irritability: Sadness and anxiety have been associated with poorly regulated blood sugar — which is the crux of diabetes. And if blood sugar gets too low, which can happen when you have diabetes, you can feel irritable, anxious, and nervous.

• Recurrent infections: Elevated blood sugar levels that are left unchecked can weaken your immune system, leading to a higher risk of infections. Research shows that the urinary tract becomes especially infection-prone in those with type 2 diabetes since the higher levels of glucose in the urine can promote bacterial growth.

• Itching: High blood sugar worsens your circulation, causing blood to pool under the skin and make it feel itchy. The high blood sugar also dries out your skin (a side effect of the dehydration caused by all that peeing), which can make it flaky and itchy as well.

• Skin tags: Small growths on the neck, eyelids, armpits, or groin can be caused by high insulin levels brought on by insulin resistance. "Insulin can act as a growth factor, and skin tags form from an overgrowth of skin cells," Ahmed says.

• Blurry vision: High blood sugar — especially when it fluctuates up and down — can affect the delicate blood vessels in your eyes, causing the lenses to swell and blurring your vision like a smudged smartphone.

Do diabetes symptoms differ by type?

The signs of diabetes are generally the same for type 1 and type 2, with a few exceptions.

• The symptoms of type 1 may show up more suddenly. With type 1 diabetes, your pancreas stops making insulin. This can cause symptoms to come on quicker compared to type 2, where insulin resistance may develop over time.

• Weight loss is more common with type 1. You might drop pounds with type 2, but it's more likely to happen with type 1.

• Tingling, pain, or numbness in the hands and feet is more common with type 2. These symptoms are often a result of having undiagnosed high blood sugar for years, which is more likely to happen with type 2.

Are diabetes symptoms different for men and women?

For the most part, diabetes symptoms are the same regardless of your sex. But there are a few exceptions. Erectile dysfunction and impotence occur in up to 80% of men with diabetes — the blood vessels and nerves involved in an erection can get damaged from high blood sugar. This is something that likely wouldn’t happen until after you’ve had diabetes for some time, so wouldn't necessarily be a sign, says Ahmed.

Women, on the other hand, are likelier to experience recurring vaginal yeast infections. (Men can get yeast infections, too, but they occur on the skin and groin.) Women are also at a higher risk of diabetes-related urinary tract infections due to the anatomical structure of their urinary tracts.

When should I see a doctor about diabetes?

While the above symptoms don’t always mean you have diabetes, experiencing any of them is a sign you should go get your blood sugar checked. And even if you don’t have symptoms, the U.S. Preventive Services Task Force recommends getting screened for diabetes every three years starting at age 45. If you have other risk factors, such as a family history of diabetes or have overweight or obesity, it’s recommended to start at age 35.

Getting tested is simple and is done using one of the following methods:

• Fasting plasma glucose test
  Glucose levels are checked after you haven't eaten for 8 to 12 hours. Your blood sugar levels will put you into one of three categories:
  99 mg/dL or less: normal
  Between 100 mg/dL and 125 mg/dL: prediabetes
  126 mg/dL or over: diabetes
  To confirm diagnosis, an abnormal result must be repeated.

• A1C test
  This blood test shows doctors an average of your blood sugar over the last three months.
  5.6% or lower: normal
  5.7% to 6.4%: prediabetes
  6.5% or higher: diabetes
  To confirm diagnosis, an abnormal result must be repeated.

• Oral glucose tolerance test
  At the start of this two-step test, you're given a very sweet drink. Over the next few hours, your blood is checked to see how your body processed the sugar load. What the results mean depends on the type of glucose drink used, but this is the gold standard for diagnosing diabetes.

• Random glucose test
  This test measures blood glucose levels at any time of day without fasting. Typically a blood sample is taken and measured on the spot. If you have symptoms of diabetes and your blood glucose is greater than 200 mg/dL, then a diabetes diagnosis may be given.