The symptoms of double diabetes may vary. Physicians may suspect double diabetes in a patient with type 1 diabetes who begins to exhibit signs and symptoms of insulin resistance and type 2 diabetes.

Possible indicators that someone with type 1 diabetes may have developed or be developing double diabetes include:

• Acanthosis nigricans (dark patches in skin folds)
  
  
• Weight gain and central obesity
  
  
• Decreased effectiveness of insulin therapy or need for rising dosages
  
  
• Chronic hyperinsulinemia
  
  
• Evidence of metabolic syndrome, such as increased blood pressure and unhealthy levels of cholesterol and triglycerides
  

  

• Presence of genes linked to insulin resistance
  
  
• Polycystic ovarian syndrome in females

In some cases, a child with double diabetes may have originally been diagnosed with type 2 diabetes but actually have type 1 and insulin resistance. Distinguishing among the various types of diabetes can be difficult. The signs and symptoms of type 1 diabetes generally develop rapidly, over several weeks or months. They can include:

• Extreme thirst (polydipsia)
• Excessive urination (polyuria)
• Increased appetite (polyphagia)
• Fatigue
• Vision changes
• Unexplained weight loss
• Sweet, fruity-smelling breath

The signs and symptoms of insulin resistance, prediabetes and type 2 diabetes usually develop over a longer period of time and may go undiagnosed for years. Some of these symptoms are similar to those of type 1 diabetes. Additional symptoms may include:

• Numbness or tingling in hands or feet
• Dry, itchy skin (pruritus)
• Slow-healing sores
• Frequent infections
• Red, swollen or tender gums