Endocrine Community
Get answers. Share advice. Learn More

What are the Symptoms of Type 1 Diabetes?

How to tell if you or your child has type 1 diabetes

With Ilana Halperin MD and Elena Christofides MD 

Type 1 diabetes is a permanent condition. That means you’ll likely have to deal with symptoms at least a few times in your life, no matter how diligently you monitor your blood sugar. We’re here to empower you with clear answers to all your pressing Qs.

What is type 1 diabetes? 

Type 1 diabetes, sometimes known as juvenile diabetes, is a chronic autoimmune condition in which your pancreas loses the ability to produce insulin. It can be triggered by a virus, such as the common cold or flu, and there is evidence that it has a genetic component as well.

Following a viral infection, your body can sometimes malfunction and respond by attacking its own cells. This process is known as an autoimmune response. In type 1 diabetes, your body’s immune system specifically attacks cells in your pancreas called beta cells, which produce the hormone insulin. In that case, damaged beta cells mean your body either stops producing enough insulin, or it can’t produce insulin at all.

What causes the symptoms of type 1 diabetes?

All type 1 diabetes symptoms are caused by that lack of insulin. You see, insulin usually acts like a gatekeeper: it takes the glucose that your body converts from carbohydrates in your food and opens your cells so that it can enter them. Once allowed inside, the glucose can then be used by your cells as fuel.

If there’s not sufficient insulin to open the gate and let the glucose in, it becomes blocked out of your cells and stays trapped in your bloodstream, causing your blood sugar to rise.

When you first develop type 1 diabetes, there may be some residual insulin remaining in your cells. This is why glucose levels can sometimes hover close enough to normal to go undetected until that initial supply is depleted.

Over time, as the insulin in your body is sapped with no new supply being produced to replace it, symptoms begin to appear and accelerate. When you reach a point where there’s no insulin and too much accumulated glucose in your bloodstream, type 1 diabetes symptoms develop rapidly and have to be addressed immediately.

It's important to note that a little bit of glucose in our blood is normal, says Ilana Halperin MD, a physician and assistant professor of medicine at the University of Toronto. “Our blood sugar starts to rise when we consume carbohydrates after a meal, and then as the insulin moves the glucose into our cells, our blood sugar levels dip back down.”

To differentiate between a temporary boost in blood sugar and chronic, elevated blood sugar levels that indicate type 1 diabetes, doctors look at a person's glycated hemoglobin levels, or A1C. A1C is the measure of the average glucose levels in a person's bloodstream for the past 90 days, with normal levels ranging from 5 to 5.5 percent. Anything above that signifies diabetes, particularly if symptoms are present.

Common symptoms of type 1 diabetes

When do people first experience symptoms of type 1 diabetes?

The majority of people with T1D first experience symptoms in childhood, typically between the ages of 4 and 14. A small number, however, develop symptoms in infancy or toddlerhood.

An even smaller subset of people with type 1 diabetes will be diagnosed as adults, after the age of 20. The onset of type 1 diabetes is slower in adults, so they might experience mild symptoms for a longer period of time before diagnosis than children typically do.

Type 1 diabetes symptoms in children look similar to the symptoms in toddlers and babies, with a few notable differences. Mood swings and irritability, for example, can affect anyone with T1D, but this common symptom might be mistaken for an ordinary temper tantrum in preverbal toddlers, or as colic in younger babies.

Type 1 diabetes symptoms in babies and toddlers include weight loss and stunted growth – a condition known as failure to thrive – which is rare in adults. Failure to thrive might be the only noticeable symptom of T1D in a baby or toddler, since older children can clue parents in to symptoms such as increased urination or blurred vision.

“One important thing we need to point out is that type 1 diabetes is often associated with children, but it happens to adults as well,” Dr. Christofides says. Adult-onset, or late-onset type 1 diabetes symptoms look slightly different and can be harder to recognize and diagnose as a result.

 “Adults typically don't have unexplained weight loss, but they do tend to experience fatigue, blurry vision, headaches, increased urination, loss of appetite, and a slowly progressing hyperglycemia,” says Dr. Christofides. T1D symptoms are quicker to develop and more acute in children because, unlike adults, it tends to be the only immune issue that they have had at that age.

What are the symptoms of type 1 diabetes?

Symptoms of Type 1 Diabetes (T1D) can differ depending on your age and if you have other health conditions. That said, here are symptoms that most people with type 1 diabetes experience before getting treatment:

  • Tiredness. A persistent and overwhelming feeling of tiredness is also known as fatigue, and it’s a classic sign of type 1 diabetes. When glucose is stuck in your bloodstream, your cells can’t use it to fuel your muscles and organs. To compensate, fatigue sets in. It’s your body’s deliberate, adaptive response to conserve the glucose it already has.
  • Increased or unquenchable thirst. When there’s too much glucose in your blood, your body tries to compensate by creating urine, pulling fluid out of your body to rid itself of the extra glucose. The more you urinate, the less fluid in your body overall, which means you get dehydrated quickly. Thirst is your body’s way of trying to compensate for that loss of fluid.
  • Headaches. Headaches are another consequence of becoming dehydrated—something that routinely happens with high blood sugar, while your body is trying to rid itself of water in order to clear the extra glucose. When your body is dehydrated, your blood level drops, making it harder for blood and oxygen to reach your brain. This chain reaction results in headaches.
  • Frequent urination. Normally, your kidneys can help absorb any excess glucose in your bloodstream. But too much glucose means that they won’t be able to absorb it all. To help flush out the glucose, your kidneys produce more urine, which—you guessed it—causes you to urinate more often. Drinking extra water due to increased thirst—another common symptom—causes you to have to go to the bathroom even more and perpetuates the cycle.
  • Abdominal pain. When your body can no longer burn glucose for fuel, it starts to burn fat—a process known as ketosis. Burning fat produces ketones, chemicals that can be measured in your blood or urine. Ketones are present when a person is on a low-carbohydrate diet or has been fasting. Having a low number of ketones in your body—also known as being in a state of ketosis—is not inherently dangerous. But having too many ketones leads to blood becoming acidic, and a life-threatening complication called diabetic ketoacidosis. Abdominal pain, particularly if it’s severe and experienced in conjunction with any of these other symptoms, is one tell-tale sign of diabetic ketoacidosis.
  • Nausea and vomiting. Nausea and vomiting are two additional signs of diabetic ketoacidosis, a condition where too many ketones build up in your bloodstream and change the acidity of your blood. Though it’s very rare, if your blood’s acidity becomes high enough, diabetic ketoacidosis can lead to coma, organ failure, and even death. This is why it’s important to seek emergency medical attention and get to a hospital right away. Most people with type 1 diabetes are actually first diagnosed when they arrive at the emergency room with diabetic ketoacidosis as children, and extreme complications are entirely preventable as long as you and your loved ones learn to recognize the signs and take them seriously.
  • Blurry vision. “As blood sugar rises over time, the sugar causes more fluid to build up behind the lens of the eye,” says diabetes specialist Elena Christofides MD. When this happens, the lens swells and changes shape, resulting in blurry vision that can take several weeks to clear even after glucose levels revert back to normal. “If you get corrective lenses and they don’t fix your eyesight, that’s another sign of diabetes,” she says. When blood-sugar levels are high for a number of years, glucose in the bloodstream can actually damage the blood vessels in the retina, causing permanent damage known as diabetic retinopathy and DME. This happens most commonly in adults, Dr. Christofides explains, because the onset of type 1 diabetes is rarer and slower, and so more likely to be overlooked until it progresses. In children, blood sugar rises too quickly for vision changes to occur before diagnosis and treatment.
  • Wounds that don’t heal. High glucose levels can cause a variety of skin problems, including dry skin due to lack of moisture, slow-healing cuts and scrapes, or chronic infections. “High blood sugar impairs the function of your cells to heal wounds properly,” says Dr. Halperin, because the cells have no glucose with which to power themselves. Not only is it harder to heal with type 1 diabetes, but it’s also easier to get injured. “Blood sugar can impact nerves in such a way where you have decreased sensation and might not feel a wound when it’s there,” says Dr. Halperin. “If a patient steps on something and doesn’t feel it, it could be in there for a week. Wounds like that are much more likely to become infected, as well as slower to heal.”
  •  Yeast infections. Yeast infections can be common in adults or children with type 1 diabetes, according to Dr. Christofides. This is because your body tries to rid itself of the excess blood sugar through sweat and urine. The excess sugar on the skin and in urine allows yeast to grow and become an infection in tucked away spots like the armpits, mouth (thrush), chest, and private parts.

What’s the difference between signs vs. symptoms of type 1 diabetes?

Type 1 diabetes symptoms are experienced by a person with diabetes, but signs of type 1 diabetes can also be noted by friends and family even if the person who is having the symptoms may not notice them or may be unable to communicate because they are in the throes of diabetic ketoacidosis. Common signs of T1D to watch out for include:

  • Weight loss, despite eating more
  • Changes to (or loss of) menstruation
  • Rapid heart rate
  • Reduced blood pressure (falling below 90/60)
  • Low body temperature (anything below 97 degrees Fahrenheit)
  • Acting or seeming “drunk” while sober, which is a sign of diabetic ketoacidosis
  • Breath that is fruity or smells like nail polish remover (yep they both have acetone) which is another sign of ketosis
  • Chronic skin infections

Type 1 diabetes complications

What are severe complications of type 1 diabetes?

Nerve damage. High blood-sugar levels over a long period of time can actually cause your blood to thicken. When this happens, the  blood has a harder time moving through your blood vessels and restricts the amount of oxygen and nutrients that can be supplied to your nerves. If left untreated, this can lead to a complication called neuropathy, or nerve damage. Nerve damage, in turn, can cause certain areas of your body to permanently lose sensation. It most commonly affects hands and feet.

Kidney damage. Thickened blood is harder to move through your body and can damage the delicate vessels inside of your kidneys. Over time, the blood vessels in your kidneys can narrow and clog, limiting their function. Because high blood sugar can damage nerves as well, people with type 1 diabetes may not be able to feel nerve signals when their bladder is full. An overfull bladder puts pressure on the kidneys and can damage them even further.

Remember, all of these symptoms and complications can be prevented if you work with your endocrinologist on a blood sugar management plan and system that works for you. Every symptom on this list can absolutely be stopped before it progresses. There is no reason a diagnosis of type 1 diabetes has to lead to anything other than an advanced awareness and understanding of how your body reacts to sugar and what to do to keep it in check when things start to get out of whack.

How can I best balance my type 1 diabetes symptoms and daily life?

Fortunately, there are medications that can help keep T1D at bay and reduce the risk of long-term complications. Type 1 diabetics who cannot make their own insulin will need a way to deliver it to their bodies, either through a pump or through injections underneath the skin with syringes or pens.

When T1D is properly controlled, a person with the condition will show no signs or symptoms, because they are playing an active role in keeping their blood sugar levels steady.

Signs and symptoms of type 1 diabetes can come on quickly, and they aren’t always obvious. Many times, they’re mistaken for other conditions. Making yourself aware of the signs and symptoms of T1D is a great way to be proactive about your health and the health of your family members. If you notice any of these signs or symptoms in yourself or a loved one, get in touch with your doctor ASAP. They can make a diagnosis by checking blood glucose levels and A1C to start treatment before there are any complications.

FAQ: Frequently Asked Questions

What are the most common symptoms of type 1 diabetes? 

Regardless of age, the most common symptoms of T1D are excessive thirst, fatigue, headache, and frequent urination.

Why do people with type 1 diabetes urinate so often?

When sugar accumulates in a person’s bloodstream, their body acts quickly to get rid of it by making extra urine. Excess glucose also triggers thirst signals in the brain, which results in drinking more and having to go to the bathroom more as well.

Why are type 1 diabetes symptoms different in children and adults?

For reasons that still aren’t totally clear, the onset of T1D is much slower in adults, often taking months for symptoms to fully manifest, whereas in children, it may only take days. High blood-sugar levels are present for longer in the bloodstream of adults, meaning that there is more opportunity for long-term damage to organs and bodily systems. For instance, untreated high blood-sugar over several months’ time can lead to nerve and kidney damage, which is a complication often found in adults who have recently received a type 1 diabetes diagnosis, but hardly ever in children.

What happens if type 1 diabetes is left untreated?

T1D symptoms, if left untreated, can lead to complications such as eye damage, kidney damage, nerve damage, heart disease, and osteoporosis. Luckily, by working with your endocrinologist to manage your blood sugar, you can avoid all of them.

Type 1 Diabetes Symptoms Fast Facts

  • Are often mistaken as symptoms for other conditions
  • Tend to appear quickly in children and but more slowly in adults
  • Can be managed and controlled with insulin
  • Are entirely preventable with proper treatment
Continue Reading
Type 1 Diabetes Causes