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Diabetes Symptoms and Complications

Medically reviewed by Leigh Ann Anderson, PharmD. Last updated on Oct 27, 2019.

Symptoms | Type 1 and Type 2 Diabetes: Differences | Complications | Prevention 


People with diabetes have high blood sugar (glucose) levels, also called hyperglycemia. This can occur in those with either type 1 diabetes and type 2 diabetes. Glucose is an important source of fuel for the body. However, if high blood sugar levels are left unchecked, complications can occur. Certain body systems can be affected, including problems with your kidneys, nerves, blood vessels, feet, and eyes. You may be at greater risk from heart disease and stroke, too. Keeping your blood sugar levels under control will help you to prevent these complications.

Symptoms of diabetes

People with type 1 or type 2 diabetes may have a range of symptoms. These symptoms might include:

  • Frequent urination (polyuria), often at night (also called nocturia)
  • Excessive thirst (also called polydipsia)
  • Extreme hunger (also called polyphagia)
  • Dry skin
  • Weakness or feeling tired much of the time (fatigue)
  • Recurring or slow-healing infections or sores
  • Ketones in the urine
  • Unexplained weight loss (usually with high blood sugars)
  • Blurred vision
  • Tingling in the hands or feet (neuropathy)
  • Mood changes, irritability
  • Nausea and vomiting (often seen with diabetic ketoacidosis in type 1 diabetes)
  • Yeast infections
  • Skin Infections
  • Urinary tract infections (UTIs)
  • Acanthosis nigricans (in type 2 diabetes; a skin disorder with dark, thick, velvet-textured skin in body folds)

What is the difference between type 1 and type 2 diabetes?

Type 1 diabetes usually occurs in childhood or adolescence. Type 1 diabetes is responsible for roughly 10% of all diabetes cases. It is considered an autoimmune disease, and weight does not play a role in its formation. The body's immune system attacks the insulin-producing cells in the pancreas.

  • Typical age at diagnosis can range from 5 to 15 years old, although there appears to be an increasing incidence in younger children.
  • Insulin treatment is required for all type 1 diabetes patients, as the pancreas has a defect in the beta cells that produce insulin hormone.
  • You cannot prevent type 1 diabetes, but you can practice a healthy lifestyle to help prevent further complications.

Type 2 diabetes accounts for the remaining 90% of diabetes cases. The incidence and prevalence of type 2 diabetes has been steadily increasing since the 1950’s. The incidence of type 2 diabetes is now increasing in adolescents and young adults, while it used to be a disease that occurred primarily in middle-age and older adults.

  • The rise in type 2 diabetes is a direct consequence of obesity, overweight and lack of exercise.
  • Most people are diagnosed with type 2 diabetes during a routine check-up when their blood tests are reviewed.
  • Insulin resistance and high levels of circulating insulin may occur many years before type 2 diabetes is diagnosed. Unlike type 1 diabetes, patients with type 2 diabetes still have the ability to produce some insulin from the pancreas.
  • About 40% of type 2 diabetics have no symptoms of their condition, and most patients with diabetes are diagnosed during a routine medical screening.
  • Many patients with type 2 diabetes can take oral or injectable diabetes medications, but eventually may need to start on insulin therapy.

Diabetes in children

The incidence of type 2 diabetes in children has risen dramatically over the last two decades. According to the Centers for Disease Control and Prevention (CDC), obesity affects 18.5 percent of all children in the United States, or roughly 13.7 million children and adolescents.

In general, children with type 2 diabetes are diagnosed at 13 to 14 years of age, coinciding with puberty. Children of certain ethnic groups, including African-American, Hispanic, American Indian, and Asian or Pacific Islander, are at higher risk for childhood obesity.

Children with type 2 diabetes run the risk of having serious health-related risks at an early age. Researchers have found that about three in four teens and young adults with type 2 diabetes had at least one diabetes-related complication, primarily due to obesity. However, diagnosis was at an earlier  stage where reversal of possible complications could begin.

Learn More: Prediabetes: Am I At Risk?

Complications of diabetes

Research has shown that the complications associated with type 2 diabetes often begin to develop well before the disease is diagnosed, usually without any symptoms. Fifty percent of people found to have type 2 diabetes are already suffering from complications. The good news is today many people with diabetes are living longer, healthier lives with fewer complications. More people are taking action to control possible risk factors that lead to these complications.

Microvascular and macrovascular complications, such as retinopathy (eye disease), nephropathy (kidney disease), neuropathy (nervous system disease) and large vessel disease are all a consequence of poor blood sugar control. These complications may be worsened by weight excess, high blood pressure, smoking, and high cholesterol levels.

Long-term complications of diabetes are more common in people who have poor blood sugar control. The best way to prevent these complications is to maintain tight control over blood sugar levels with regular blood glucose testing and appropriate medical care, including drug treatments. It is also important to have annual eye and foot exams as well as kidney function tests.


Very low blood sugar levels (also called hypoglycemia) can also result in complications. Hypoglycemia occurs when there's too much insulin and not enough sugar (glucose) in the blood. Your blood sugar levels can drop due to an infection, too much or too little diabetes medicine, exercise, skipping meals, or other medications you take, such as high blood pressure drugs.

Hypoglycemia (low blood sugar less than 70 mg/dL) may occur in patients who use insulin or take certain oral diabetes medications (sulfonylureas or meglitinides). Treatment of hypoglycemia is important, as if it is left untreated it can lead to seizures, loss of consciousness, and rarely death.

  • Symptoms of hypoglycemia may include a fast heart rate, sweating, shakiness, weakness, hunger, and anxiety.
  • Patients with diabetes should know these warning symptoms of hypoglycemia and have glucose tablets or a 20 gram carbohydrate snack on hands at all times to treat low blood sugar.
  • However, in patients who take alpha-glucosidase inhibitors such as Precose (acarbose) or Glyset (miglitol), an episode of hypoglycemia is best treated with glucose tablets because these drugs will prevent the digestion of polysaccharides often found in carbohydrate-containing foods.
  • If you lose consciousness, you'll need an injection of the hormone glucagon that helps to release sugar into your blood. Seek emergency care immediately.

Diabetic ketoacidosis (DKA)

Diabetic ketoacidosis is more common in patients with type 1 diabetes, but may still occur rarely in those with type 2 diabetes. DKA occurs due to a lack of insulin, and the body responds by burning fatty acids instead of glucose. The result is a high levels of acidic ketone bodies. Check your urine for ketones, especially when you're sick.

DKA is an urgent, possibly fatal, medical condition that requires insulin treatment, fluid replacements and correction of electrolytes. Contact emergency medical personnel or call 911.

  • early symptom of DKA include: thirst, dry mouth, frequent urination,
  • later signs and symptoms of DKA include nausea, vomiting, shortness of breath, fruity breath odor, confusion and possibly coma.

Gestational diabetes

Diabetes diagnosed during pregnancy can raise the risk for serious complication for mother and baby. Pre-eclampsia (a serious high blood pressure in pregnancy) can occur.

Your doctor will most likely screen you for gestational diabetes during your second trimester if you are at average risk for gestational diabetes.

Learn more: Gestational Diabetes.

Long-term complications of diabetes

  • Cardiovascular (heart) disease
    • a major complication and the leading cause of premature death among people with diabetes. Includes chest pain (angina), heart attack, stroke, and coronary artery disease (atherosclerosis).
    • About 68% of people over age 65 with diabetes die from heart disease, and roughly 16% die from stroke.
      • Symptoms of a heart attack may include: shortness of breath, dizzy, faint, sweating, nausea, chest pain, pain in shoulders, jaw, left arm.
      • Symptoms of a stroke may include: sudden numbness or weakness in face, difficulty speaking or understanding words, vision changes, loss of balance, brief loss of consciousness, sudden loss of bodily movements, intense headache.
    • Tight blood sugar control, and use of cholesterol medications like statins, blood pressure drugs like ACE inhibitors, metformin and aspirin may reduce cardiovascular risk in diabetic patients.
  • Kidney damage
    • diabetes is a leading cause of renal (kidney) nephropathy and chronic kidney disease (CKD) which can lead to end-stage renal disease (ESRD). This is a serious condition which may result in the need for dialysis or kidney transplantation.
    • Diabetic patients are often prescribed ACE inhibitor or angiotensin-II receptor blocker medications to help protect the kidney and provide blood pressure control.
    • Roughly 40% of diabetic patients may develop diabetic nephropathy (kidney disease) without treatment.
      • Symptoms of kidney disease may include: swelling or water-retention, especially in the hands, feet or face, weight gain from water retention, itching, tiredness.
  • Eye disease or blindness
    • diabetes is a major cause of blindness in the U.S., and is the leading cause of new blindness in working-aged Americans.
    • Diabetic retinopathy (damage to the blood vessels in the retina) alone accounts for at least 12% of new cases of blindness each year in the U.S. Diabetes can also worsen glaucoma and cataracts.  
    • Early detection can prevent or delay blindness in 90% of people with diabetes.
      • Symptoms of eye disease may include: blurred vision, tearing, spots in your vision, vision loss.
  • Nerve damage (neuropathy) and amputations
    • around 60% to 70% of diabetics have some type of nerve damage or diabetic neuropathy due to high blood sugars in blood vessels. Neuropathy can also affect internal organs.
    • damage to the nerves can ultimately lead to ulceration, infection and amputation of the toes, feet or lower leg. 
      • Symptoms may include: decreased, painful, or burning sensation in feet , numbness, constipation, diarrhea, problems with sexual function.
    • Amputation risk can be lowered by smoking cessation, strict glucose control, management of high blood pressure and lipid levels, and prompt treatment of lower extremity infections.
  • Dental disease
    • periodontal or gum diseases are more common among people with diabetes than those without diabetes. Almost one third of people with diabetes have severe periodontal diseases.
    • Preventive and routine periodontal care is important for patients with diabetes.
  • Obstructive sleep apnea
    • Obstructive sleep apnea is more common in patients who are overweight or obese and has been linked with altered glucose metabolism and insulin resistance.
      • Signs or symptoms may include: snoring, daytime sleepiness, frequent nighttime awakenings, gasping and suddenly waking up.
  • Depression
    • Patients with diabetes may be more prone to depression, which can worsen as diabetes complications worsen.
      • symptoms may include: withdrawal from family and friends, loss of interest for social activities, mood changes or irritability, difficulty sleeping, sadness and tearfulness, thoughts of suicide, changes in appetite, loss of interest in self-care.

If you experience any of the symptoms of these complications, contact your health care professional or seek emergency medical help (call 911).

How to Prevent Diabetes Complications

Maintaining a healthy lifestyle with adherence to a proper diet, weight loss if needed, and daily exercise is the foundation of a prevention plan for diabetes complications.

  • Consider working with a nutritionist or dietician to examine your eating habits and food choices. Consider a plant-based diet with added whole grains for fiber.
  • Engage in physical activity at least 150 minutes per week (at least 30 minutes each day for 5 days per week). Several shorter sessions equaling 10 or 15 minutes can do just as much good.
  • Maintain strict daily blood sugar control.
  • Lose weight if your overweight: even a 7% weight-loss can have positive benefits. For example, if you weight 200 lbs, losing just 14 lbs. lowers your risk for complications.
  • Visit your doctor as recommended and take your medications as prescribed.
  • Avoid being sedentary or sitting for long periods of time.
  • Make appointments to monitor your feet (podiatrist) and eyes (optician or ophthalmologist). Don't forget to visit your dentist, dietician and of course your primary care doctor for your regular check-ups.
  • Manage your ABCs:
    • A: A1C test - have this as recommended by your doctor to manage your target blood sugar goals and review long-term control.
    • B: Blood pressure - Keep your blood pressure at the levels suggested by your doctor, usually less than 130/80 mm/Hg. Controlling blood pressure is essential to help prevent heart disease, stroke, peripheral artery disease, and kidney, eye and nerve disease.
    • C: Cholesterol - keep your cholesterol levels (LDL, HDL, triglycerides) within the recommended range.
    • s: Stop smoking, or never start smoking. Smoking doubles the risk for heart disease in people with diabetes.

See Also


  1. Department of Health and Human Services. NIH. National Heart, Lung and Blood Institute. Managing Overweight and Obesity in Adults: Systematic Evidence Review from the Obesity Expert Panel. Accessed Dec 19, 2019 at:
  2. Diabetes in Children and Teens. Medline Plus. Accessed Dec 19, 2019 at
  3. Youth With Type 2 Diabetes Often Face Complications. Feb. 28, 2017. 
  4. Putting the Brakes on Diabetes Complications. US Centers for Disease Control and Prevention (CDC). Accessed October 27, 2019 at
  5. Cardiovascular Disease and Diabetes. American Heart Association (AHA). Accessed October 27, 2019 at
  6. American Diabetes Association. Complications. Accessed October 27, 2019 at

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.