Early Signs and Symptoms of Diabetes
Diabetes often begins quietly. Many people live with high blood sugar for months or even years before they are diagnosed. Knowing the early warning signs, and knowing that some people have no signs at all, can help you seek testing sooner and lower the risk of complications. This article walks through common symptoms, how they differ between type 1 and type 2 diabetes, signs in children, and when to get medical help.
Why symptoms can be easy to miss
According to the CDC's page on diabetes symptoms, type 1 and type 2 diabetes often develop slowly over time, and both can start with few or no symptoms. Type 2 diabetes symptoms in particular can take several years to develop, and some people never notice any. Early symptoms like tiredness or thirst are also easy to blame on a busy life, hot weather, or getting older.
That is why screening is so important. If you have risk factors, a simple blood test can identify diabetes or prediabetes long before you feel unwell.
Common symptoms of diabetes
The CDC lists the following symptoms that can occur with both type 1 and type 2 diabetes:
- Frequent urination, often including waking at night to urinate.
- Increased thirst and hunger.
- Losing weight without trying.
- Fatigue (tiredness).
- Feeling irritable or moody.
- Blurry vision.
- Frequent urinary tract infections or yeast infections.
The American Diabetes Association and NIDDK describe similar warning signs, and NIDDK also mentions sores that do not heal and numbness or tingling in the feet or hands.
Why high blood sugar causes these symptoms
Understanding the "why" can make the symptoms easier to recognize:
- Thirst and frequent urination: When glucose in the blood is very high, the kidneys cannot reabsorb all of it. Extra glucose spills into the urine and pulls water with it, so you urinate more and become dehydrated and thirsty.
- Hunger and weight loss: If insulin is missing or not working well, cells cannot use glucose for energy. The body may break down fat and muscle for fuel, which can cause weight loss even when you are eating more.
- Fatigue: Cells that are short on usable energy, combined with dehydration, can leave you feeling tired.
- Blurry vision: High glucose can change fluid levels in the lens of the eye, temporarily affecting focus.
- Infections and slow healing: High blood sugar can affect circulation and the immune response, which may make infections more common and wounds slower to heal.
Symptoms more typical of type 1 diabetes
The CDC notes that people with type 1 diabetes in its early stages may have no symptoms, but as it progresses symptoms can appear suddenly, over just a few weeks or months, and can be severe. In addition to the common symptoms above, people with type 1 may experience:
- Nausea
- Vomiting
- Stomach pain
- Diabetic ketoacidosis (DKA)
What is diabetic ketoacidosis (DKA)?
When the body has too little insulin, it starts burning fat for energy at a rapid rate, producing acids called ketones. If ketones build up, the blood becomes acidic. DKA is a medical emergency. Warning signs can include nausea, vomiting, stomach pain, deep or rapid breathing, fruity-smelling breath, extreme tiredness, and confusion. Sometimes DKA is the first sign that someone has type 1 diabetes. It can also happen in people with type 2 diabetes, though it is less common. If you suspect DKA, seek emergency medical care right away.
Symptoms more typical of type 2 diabetes
The CDC lists some additional symptoms that are more common in type 2 diabetes:
- Cuts, sores, or wounds that are very slow to heal.
- Dark patches of skin around the neck, armpits, or groin. This skin change, called acanthosis nigricans, is associated with insulin resistance.
- Numbness or tingling in the hands or feet, which can be a sign of nerve damage.
Because type 2 diabetes develops slowly, some people are diagnosed only after a complication appears, such as an eye problem found during a routine eye exam. That is one more reason to know your risk factors.
Signs in children
Type 1 diabetes is frequently diagnosed in childhood, though it can occur at any age. The CDC notes that in children, unexplained bed-wetting or more frequent accidents in a child who was already toilet trained could be a sign of type 1 diabetes. Parents may also notice a child is unusually thirsty, hungry, tired, or losing weight. Type 2 diabetes is also increasingly diagnosed in children and teens. If you notice these signs in a child, contact their health care provider promptly.
Gestational diabetes usually has no symptoms
Diabetes that develops during pregnancy usually does not cause symptoms. For that reason, the CDC advises that pregnant people be tested between 24 and 28 weeks of pregnancy, or earlier if they have risk factors.
Prediabetes: no symptoms, but a real risk
Prediabetes rarely causes clear symptoms. You can have it for years without knowing. The CDC estimates that about 8 in 10 adults with prediabetes are unaware of it. Our prediabetes guide explains who should be tested and what can be done.
Who should get tested?
Because symptoms are unreliable, knowing your risk is important. The CDC lists risk factors for prediabetes and type 2 diabetes including:
- Having overweight
- Being 45 years or older
- Having a parent, brother, or sister with type 2 diabetes
- Being physically active less than 3 times a week
- Ever having gestational diabetes, or giving birth to a baby who weighed more than 9 pounds
- Having polycystic ovary syndrome (PCOS)
The CDC also notes that African American, Hispanic/Latino American, American Indian, Alaska Native, Pacific Islander, and some Asian American people are at higher risk. If any of these apply to you, ask your health care provider whether you should be tested, even if you feel fine.
How testing works
Diagnosis is made with blood tests such as the A1C, fasting plasma glucose, or oral glucose tolerance test. Home blood glucose meters and over-the-counter test strips are useful for monitoring once diagnosed, but they are not meant to diagnose diabetes. See A1C and blood sugar targets for what results mean.
When to seek care
Make an appointment if you notice ongoing thirst, frequent urination, unexplained weight loss, blurry vision, slow-healing sores, frequent infections, or tingling in your hands or feet, or if you have risk factors and have not been tested recently.
Get emergency help if someone has symptoms of DKA (vomiting, abdominal pain, rapid breathing, fruity breath, confusion), is very drowsy or hard to wake, or is severely dehydrated.
Key takeaways
- Common signs include thirst, frequent urination, hunger, unexplained weight loss, fatigue, and blurry vision.
- Type 1 symptoms can come on quickly and may include nausea, vomiting, and DKA.
- Type 2 diabetes and prediabetes often have mild or no symptoms, so testing based on risk factors is essential.
- Early diagnosis and treatment can help prevent serious complications.
Sources
Links to the sources cited above appear in the text. We rely on the Centers for Disease Control and Prevention (CDC), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), and the American Diabetes Association (ADA).
Related guides: Diabetes basics
- What Is Diabetes? Type 1 vs. Type 2 Explained
- Type 1 Diabetes: Causes, Diagnosis, and Treatment
- Type 2 Diabetes: A Complete Overview
- Gestational Diabetes: What to Know During and After Pregnancy
- Prediabetes: What It Is and How to Reverse Course
- Diabetes Symptoms in Women: Signs to Know
- Diabetes in Children and Teens: A Guide for Families
- Diabetes Myths vs. Facts
- LADA (Type 1.5 Diabetes): Autoimmune Diabetes in Adults
- MODY and Rare Types of Diabetes
- Insulin Resistance: Causes, Signs, and How to Improve It