Topic Overview
High blood sugar (hyperglycemia) is most often seen in people who have diabetes that isn't well controlled. The symptoms of high blood sugar can be mild, moderate, or severe.
Mild high blood sugar
If your blood sugar levels are consistently higher than your target range (usually 11 mmol/L to 20 mmol/L, and 11 mmol/L to 14 mmol/L in children), you may have mild symptoms of high blood sugar. You may urinate more than usual if you are drinking plenty of liquids. Some people who have diabetes may not notice any symptoms when their blood sugar level is in this range. The main symptoms of high blood sugar are:
- Increased thirst.
- Increased urination.
- Weight loss.
- Fatigue.
- Increased appetite.
Young children are unable to recognize symptoms of high blood sugar. Parents need to do a home blood sugar test on their child whenever they suspect high blood sugar.
If you don't drink enough liquids to replace the fluids lost from high blood sugar levels, you can become dehydrated. Young children can become dehydrated very quickly. Symptoms of dehydration include:
- A dry mouth and increased thirst.
- Warm, dry skin.
Moderate to severe high blood sugar
If your blood sugar levels are consistently high (usually above 20 mmol/L in adults and above 14 mmol/L in children), you may have moderate to severe symptoms of high blood sugar. These symptoms include:
- Blurred vision.
- Extreme thirst.
- Light-headedness.
- Flushed, hot, dry skin.
- Restlessness, drowsiness, or difficulty waking up.
If your body produces little or no insulin (people with type 1 diabetes and some people with type 2 diabetes), you also may have:
- Rapid, deep breathing.
- A fast heart rate and a weak pulse.
- A strong, fruity breath odour.
- Loss of appetite, belly pain, and/or vomiting.
If your blood sugar levels continue to rise, you may become confused and lethargic. You also may become unconscious if your blood sugar levels are very high.
Credits
Current as of: July 28, 2021
Author: Healthwise Staff
Medical Review:
E. Gregory
Thompson MD - Internal Medicine
Donald Sproule MDCM, CCFP - Family Medicine
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine
Rhonda O'Brien MS, RD, CDE - Certified Diabetes Educator
Frequent urination, fatigue, and blurry vision are just some of the symptoms of uncontrolled type 2 diabetes.
Reviewed: August 22, 2019
Does Not Having Symptoms Mean Diabetes Is Being Managed Well?
Being Extra Thirsty and Having to Urinate More Than Usual
This is a common but not-so-obvious sign of blood sugar that is too high: feeling really thirsty and needing to drink more than usual. “Excessive urination, known as polyuria, occurs when glucose builds up in your blood, and your kidneys begin working harder to get rid of the extra glucose,” says Zanini. If your kidneys can’t keep up and adjust blood sugar so that it returns to a normal level, the excess sugar is flushed out of your body through urine, she adds. You may become dehydrated and get dizzy.
RELATED: Can Chronic Dehydration Lead to Type 2 Diabetes?
You’re Hungrier Than Usual but Losing Weight
Many people with uncontrolled high blood sugar find that they’re hungrier than usual, which signals a symptom called polyphagia, MedlinePlus notes. And although you’re eating more, you may be losing weight for no apparent reason if your blood sugar levels are too high, according to the Mayo Clinic.
“Since your body is not getting energy from the preferred source, glucose, it has to turn to muscle and fat,” Zanini explains. “When your body starts breaking down muscle and fat for energy, you experience unintentional and unhealthy weight loss.” In addition to these changes in weight and appetite, you may notice weakness in your muscles and experience more frequent falls, Emanuele adds.
You Feel Tiredness and Fatigue Constantly
You Have Noticeably Blurry Vision and Frequent Headaches
You may notice that your vision isn’t as clear as it used to be and that things may appear a bit blurry. High blood sugar levels can lead to swollen lenses in your eye from fluid leaking in, according to the Joslin Diabetes Center in Boston. This changes the shape of the lens, which makes it unable to properly focus, causing blurred vision. You may also find yourself struggling at work, having difficulty driving, and suffering from frequent headaches, Emanuele notes.
RELATED: How Diabetes Can Damage Your Eyes
You Develop Sores That Tend to Heal More Slowly Than Usual
You Notice Tingling and Numbness in Your Hands or Feet
You’re Developing Blisters, Dryness, or Other Skin Changes
Small pieces of extra skin, called skin tags, may form in the creases of skin, especially if you have diabetes and you’re trying to find ways to manage your weight, notes the ADA. Dark, thick areas of soft skin (called acanthosis nigricans) may form on the back of the neck or hands, armpits, face, or other areas. These can be a sign of insulin resistance, Zanini says. Blisters, infections, dryness, itchiness, discolorations, and abnormalities of the skin can all be warning signs of high blood sugar. Check with your doctor if these skin changes develop.
RELATED: 8 Ways to Maintain Healthy Skin With Type 2 Diabetes
You’re Getting Yeast Infections More Often Than Usual
Hyperglycemia may lead you to get more frequent genital yeast infections. The culprit is often a type of yeast (a fungus) known as Candida albicans, per the ADA. According to the Centers for Disease Control and Prevention, in females the symptoms can include: vaginal itching, redness or soreness; pain during sexual intercourse; pain or discomfort during urination; and thick, abnormal vaginal discharge. While yeast infections are common in people who don’t have diabetes, having more glucose in your blood puts you at higher risk of getting them. “The yeast feeds off the glucose, and if your blood sugar is high there’s more glucose in the urinary tract,” explains Bandukwala. Uncircumcised men with hyperglycemia are also at risk, he says.
“We’re also seeing this happen a little more now with patients who take SGLT-2 inhibitors, which force the body to expel more glucose through the urine,” the endocrinologist adds. The FDA has added a warning to the prescribing information for SGLT-2 inhibitors about a far more rare — and potentially fatal — genital condition, known as necrotizing fasciitis of the perineum, or Fournier’s gangrene (commonly known as a flesh-eating disease).
RELATED: What Are the Pros and Cons of SGLT2 Inhibitors for Type 2 Diabetes?
Swollen or Bleeding Gums, Which Increase Your Infection Risk
Gum disease is a complication of diabetes, notes the National Institute of Diabetes and Digestive and Kidney Disease. It can also make diabetes harder to control, because the body’s response to infection is to release more glucose into the bloodstream, according to the ADA.
Your saliva contains glucose; and the more it contains, the more there is to feed the bacteria that combine with food in your mouth to form plaque and cause gum disease. Symptoms can include red or inflamed gums at first. If they are unaddressed, they can progress to periodontitis, which can cause your gums to pull away from your teeth, the appearance of pus or ulcers, or even tooth loss, notes the Mayo Clinic. Get your blood sugar under control and see a dental professional to prevent damage to your gums and teeth.
Additional reporting by Diana Rodriguez and Andrea Peirce.