Symptoms of type 1 diabetes usually develop quickly, over a few days to weeks, and are caused by blood sugar levels rising above the normal range (hyperglycemia). Early symptoms may be overlooked, especially if the person has recently had an illness, such as influenza (flu). Early symptoms include:

Frequent urination, which may be more noticeable at night. Some young children who have learned to use the toilet may start wetting the bed during naps or at night.
Extreme thirst and a dry mouth.
Weight loss.
Increased hunger (possibly).

Sometimes the blood sugar level rises excessively before a person knows something is wrong. Because insulin is not available, the cells in the body are unable to get the sugar (glucose) they need for energy. The body begins to break down fat and muscle for energy. When fat is used for energy, ketones-or fatty acids-are produced and enter the bloodstream, causing the chemical imbalance diabetic ketoacidosis. This is a life-threatening condition. Symptoms of diabetic ketoacidosis are:

Flushed, hot, dry skin.
Loss of appetite, abdominal pain, and vomiting.
A strong, fruity breath odor (similar to nail polish remover or acetone).
Rapid, deep breathing.
Restlessness, drowsiness, difficulty waking up, confusion, or coma. Young children may lack interest in their normal activities.