High blood sugar symptoms: What are the early signs of high blood sugar?

Hyperglycemia is the medical term for high blood sugar levels, or high blood glucose levels. Keeping blood sugar in a target range, or normal range, is important for overall health, as well as for preventing long-term health complications. People with diabetes or prediabetes experience hyperglycemia. It is important to recognize the symptoms of high blood sugar (such as increased thirst and urination), as well as test your blood sugar, and know what to do if your blood sugar is high. 

This article will focus on high blood sugar, or hyperglycemia.

What are the early signs of high blood sugar (hyperglycaemia)?

Early signs of high blood sugar may include:

• Feeling very thirsty

• Having to urinate frequently

• Hunger

• Weight loss

• Itchy skin

• Darkened skin around the neck and armpits

• Tiredness

• Slow wound healing

• Yeast infections

• Blurred vision

• Mood changes such as irritability. 

Testing blood sugar will also alert individuals to a high blood sugar level. For adults who do not have diabetes, a normal fasting blood sugar is 70-99 mg/dl. A fasting blood sugar is measured after you have not had anything to eat or drink (except water) for at least 8 to 12 hours. A fasting blood sugar of 100 to 125 mg/dl is considered to be in the prediabetes range, and a fasting blood sugar of 126 mg/dl or more is considered to be in the diabetes range.

What is diabetic ketoacidosis (DKA)?

Diabetic ketoacidosis, or DKA, is a life-threatening condition that can lead to coma or death if untreated. DKA is more common in people with Type 1 diabetes than those with Type 2 diabetes. 

DKA occurs when the body isn’t moving sugar into the cells, so it starts to burn fat for energy. This makes chemicals called ketones, which make the blood acidic. This can occur when your blood sugar is not controlled or when you are getting sick. When ketone levels are too high, they can poison the body. DKA is a medical emergency and requires treatment in the hospital. 

Early symptoms of DKA include excessive thirst and/or urination, high blood sugar, and the presence of ketones in the blood or urine. Then, other symptoms appear, such as tiredness, flushed skin, nausea, vomiting, stomach pain, difficulty breathing, fruity breath, and confusion. 

Types of high blood sugar: How can I tell which one I have?

Insulin resistance and prediabetes

Insulin is a hormone made by the pancreas that regulates blood sugar. Insulin helps move blood sugar to the cells, where it can be used for energy. People with insulin resistance do not respond well to insulin, so the pancreas makes more insulin. If the pancreas continues to make enough insulin, blood sugar levels will stay in the normal range.  

About one in every three adults in the US has prediabetes. Prediabetes means that you have high blood sugar levels but not high enough to be diagnosed with diabetes. While people with a normal blood sugar have a fasting blood sugar of 70-99 mg/dl, people with prediabetes generally have a fasting blood sugar of 100-125 mg/dl. Without intervention (such as diet, exercise, and possibly medication), over time, many people with prediabetes develop Type 2 diabetes. 

People with insulin resistance or prediabetes may not have any symptoms. There may be darkened skin in the armpits or around the neck—this is called acanthosis nigricans. There may also be skin tags in these areas.   

Diabetes

People with diabetes have a fasting blood sugar of 126 mg/dl or more. About 11% of the US population has diabetes, with many more going undiagnosed. 

Type 1 diabetes is an autoimmune condition where the immune system attacks cells in the pancreas, preventing the pancreas from making enough insulin to bring down blood sugar. People with Type 1 diabetes will always require insulin to replace the insulin that the pancreas is not making. 

Type 2 diabetes generally will require treatment such as lifestyle changes (including diet and exercise), oral medication such as Glucophage (metformin) or injectable medication such as Trulicity, and in some cases, insulin.

Diabetes is considered a progressive disease. Having high blood sugar for a long time can lead to long-term complications. There is less chance of complications with tightly controlled blood sugar. This means that you keep your blood sugar in the target, or normal, range, for as much time as possible.   

When to see a doctor for high blood sugar symptoms

If you are testing your blood sugar at home and your fasting blood sugar is 100 mg/dl or higher, contact your healthcare provider. If you notice symptoms mentioned above, such as increased thirst and urination, hunger, and weight loss, even if you are not checking your blood sugar at home, contact your healthcare provider right away. It is important to get a timely diagnosis so that you can start getting your blood sugar into a normal range right away. People with Type 1 diabetes, often children or young adults, are usually admitted to the hospital for several days when diagnosed. 

You can start with your primary care provider, or go directly to an endocrinologist. Your healthcare provider may order some tests, including fasting blood sugar and hemoglobin A1C. The hemoglobin A1C is a measure of blood sugar control over a period of about three months. 

• A normal hemoglobin A1C for people without diabetes is less than 5.7%. 

• An A1C of 5.7 to 6.4% is in the prediabetes range.

• An A1C of 6.5% or higher is in the diabetes range. 

Complications of hyperglycaemia

It is important to keep blood sugar in the normal range as much as possible. If high blood sugar is untreated over a long period of time, it can lead to long-term health complications, including:

• Eye problems, including vision loss, sensitivity to light, and blindness

• Infections and sores on the feet and skin. In some cases, an amputation may be required.

• High blood pressure, high cholesterol, heart attack, heart disease, stroke, and circulation problems

• Nerve damage, causing pain, burning, numbness, tingling, and loss of feeling. Nerve damage can also make it difficult for men to achieve and maintain an erection.

• Digestive problems, including constipation or diarrhea

• Kidney problems, which may require dialysis or a kidney transplant

• A weakened immune system, making infections (and complications from infections) more likely

• Depression 

• Increased risk of dementia and osteoporosis

• Women may have irregular periods and problems getting pregnant

How to treat high blood sugar and diabetes

For people with prediabetes, diet and exercise will be recommended. If this is not enough, a prescription medication may be required. 

People with Type 1 diabetes always require insulin. For people with Type 2 diabetes, healthcare providers will recommend dietary changes and exercise. Oral or injectable prescription is generally required, and in some cases, insulin may be needed to help control blood sugar levels. 

Examples of medications used along with diet and exercise to control blood sugar in adults with Type 2 diabetes include:

• Biguanides: this drug class includes Glucophage (metformin), which is available in immediate-release and extended-release formulations

• Sulfonylureas such as Amaryl (glimepiride), Glucotrol (glipizide), and Micronase (glyburide)

• Alpha glucosidase inhibitors such as Glyset (miglitol) and Precose (acarbose)

• Thiazolidinediones, also known as glitazones, such as Actos (pioglitazone)

• DPP-4 inhibitors, also known as gliptins, such as Januvia (sitagliptin), Nesina (alogliptin), and Tradjenta (linagliptin)

• SGLT2 inhibitors such as Farxiga (dapagliflozin), Invokana (canagliflozin), and Jardiance (empagliflozin)

• Meglitinides such as Prandin (repaglinide) or Starlix (nateglinide)

• GLP-1 receptor agonists such as the injections Trulicity (dulaglutide), Victoza (liraglutide), and Ozempic (semaglutide)—and the oral drug Rybelsus (semaglutide)  

There are also many combination medications that combine ingredients from two or three drug classes. A few examples are ActoPlus Met (pioglitazone and metformin), Glyxambi (linagliptin and empagliflozin), Janumet (sitagliptin and metformin), and Trijardy XR (linagliptin, empagliflozin, and metformin). 

Some individuals with Type 2 diabetes, and all individuals with Type 1 diabetes, will require insulin. Insulin is most commonly administered by a pen injection or through an insulin pump. There are various types of insulin, including fast-acting and long-acting insulin. Long-acting insulin may be used once or twice daily, and is referred to as basal insulin. This insulin helps keep blood sugar steady in the absence of food. Fast-acting insulin can be used before meals or to bring down high blood sugar. 

There are many options available to treat high blood sugar. Your healthcare provider will discuss options and determine which is the best treatment for you. 

Living with high blood sugar

When you have high blood sugar, focusing on keeping your blood sugar level in the target range will help reduce long-term health complications. Here are some tips for living with high blood sugar:

• Check your blood sugar as directed—or ask your doctor about a continuous glucose monitor (CGM)—and report numbers to your doctor.  

• Maintain healthy blood pressure and cholesterol.

• Keep all doctor appointments and lab work appointments.

• Exercise (ask your healthcare professional before starting a new exercise program).

• Maintain a healthy diet. You can consult a registered dietician for advice on an eating plan that helps control blood sugar.

• Take your medications and/or insulin as directed and do not skip doses. In addition to medications for diabetes, your healthcare professional may also prescribe medications for other health conditions or to prevent certain complications. Your doctor will review your treatment plan with you. 

• Avoid smoking. If you do smoke, ask your healthcare provider about quitting.

• Check your feet daily, and get regular foot exams as recommended by your healthcare provider. Ask your provider what kind of socks and shoes you should wear.

• Get regular dental exams, at least every 6 months, and see your eye doctor at least once a year or as recommended by your health care team. 

FAQs about high blood sugar symptoms

How do you feel when your blood sugar is high?

You may feel very thirsty and need to urinate a lot. Other symptoms may include hunger, weight loss, blurry vision, dark skin around the neck and armpits, slow wound healing, and irritability.

How do you bring blood sugar down quickly?

This will depend on the type of diabetes you have. People with Type 1 diabetes, or those with Type 2 diabetes who use insulin, will use their fast-acting insulin to bring blood sugar down. Drinking extra water and exercising are other ways to help bring down blood sugar. You can ask your physician for specific medical advice on how to lower your blood sugar. 

What causes high blood sugar in women?

In men or women, high blood sugar can be caused by various factors, including prediabetes or diabetes. People with Type 1 diabetes may have high blood sugar when they do not administer enough insulin. Blood sugar can also increase when you eat more than planned or exercise less than planned, or due to certain stresses on the body such as illness, or other stress like family arguments. 

What’s next? Additional resources for people with high blood sugar symptoms

Test and diagnostics

• Manage blood sugar, Centers for Disease Control and Prevention (CDC)

• The big picture: checking your blood glucose, American Diabetes Association 

Treatments

• Diabetes treatments and medications, SingleCare

• Hyperglycemia (high blood glucose), American Diabetes Association

• Insulin basics, American Diabetes Association

• Oral medication, American Diabetes Association

Scientific studies and clinical trials

• Clinical trials, American Diabetes Association

• Clinical trials for diabetes, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

More information on related health conditions

• High blood sugar - self care, U.S. National Library of Medicine - Medline Plus. 

• What is diabetes?, Centers for Disease Control and Prevention (CDC)

• What is diabetes?, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)

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