The signs and symptoms of type 1 diabetes in children usually develop quickly, over a period of weeks. These signs and symptoms include:

• Increased thirst and frequent urination. Excess sugar building up in your child's bloodstream pulls fluid from tissues. As a result your child might be thirsty — and drink and urinate more than usual. A young, toilet-trained child might suddenly experience bed-wetting.
• Extreme hunger. Without enough insulin to move sugar into your child's cells, your child's muscles and organs lack energy. This triggers intense hunger.
• Weight loss. Despite eating more than usual to relieve hunger, your child may lose weight — sometimes rapidly. Without the energy sugar supplies, muscle tissues and fat stores simply shrink. Unexplained weight loss is often the first sign of type 1 diabetes to be noticed in children.
• Fatigue. Lack of sugar in your child's cells might make him or her tired and lethargic.
• Irritability or behavior changes. In addition to mood problems, your child might suddenly have a decline in performance at school.
• Fruity-smelling breath. Burning fat instead of sugar produces certain substances (ketones) that can cause a fruity breath odor.
• Blurred vision. If your child's blood sugar is too high, fluid may be pulled from the lenses of your child's eyes. Your child might be unable to focus clearly.
• Yeast infection. Girls with type 1 diabetes may have a genital yeast infections. Babies can develop diaper rashes caused by yeast.

The exact cause of type 1 diabetes is unknown. But in most people with type 1 diabetes, the body's immune system — which normally fights harmful bacteria and viruses — mistakenly destroys insulin-producing (islet) cells in the pancreas. Genetics and environmental factors appear to play a role in this process.

Insulin performs the critical job of moving sugar (glucose) from the bloodstream to the body's cells. Sugar enters the bloodstream when food is digested.

Once the islet cells of the pancreas are destroyed, your child produces little or no insulin. As a result, glucose builds up in your child's bloodstream, where it can cause life-threatening complications.

Risk factors for type 1 diabetes in children include:

• Family history. Anyone with a parent or siblings with type 1 diabetes has a slightly increased risk of developing the condition.
• Genetic susceptibility. The presence of certain genes indicates an increased risk of developing type 1 diabetes.
• Race. In the United States, type 1 diabetes is more common among non-Hispanic white children than among other races.

Environmental risk factors might include:

• Certain viruses. Exposure to various viruses may trigger the autoimmune destruction of the islet cells.
• Diet. No specific dietary factor or nutrient in infancy has been shown to play a role in the development of type 1 diabetes. However, early intake of cow's milk has been linked to an increased risk of type 1 diabetes, while breast-feeding might lower the risk. The timing of the introduction of cereal into a baby's diet also may affect a child's risk of type 1 diabetes.

Complications of type 1 diabetes develop gradually. If blood sugar levels aren't well-controlled over a prolonged period of time, diabetes complications can eventually be disabling or even life-threatening.

Complications can include:

• Heart and blood vessel disease. Diabetes dramatically increases your child's risk of developing conditions such as coronary artery disease with chest pain (angina), heart attack, stroke, narrowing of the arteries (atherosclerosis) and high blood pressure later in life.
• Nerve damage. Excess sugar can injure the walls of the tiny blood vessels that nourish your child's nerves, especially in the legs. This can cause tingling, numbness, burning or pain. Nerve damage usually happens gradually over a long period of time.
• Kidney damage. Diabetes can damage the numerous tiny blood vessel clusters that filter waste from your child's blood. Severe damage can lead to kidney failure or irreversible end-stage kidney disease, requiring dialysis or a kidney transplant.
• Eye damage. Diabetes can damage the blood vessels of the retina, which may lead to poor vision and even possibly causing blindness. Diabetes can also lead to cataracts and a greater risk of glaucoma.
• Skin conditions. Diabetes may leave your child more prone to skin problems, including bacterial infections, fungal infections and itching.
• Osteoporosis. Diabetes may lead to lower than normal bone mineral density, increasing your child's risk of osteoporosis as an adult.