Diagnosis of hyperhidrosis typically begins with a complete medical history and a thorough physical examination. The physician will usually address factors such as:

• The part of the body initiating the sweating response
  
  
• The rate of sweat production
  
  
• Whether sweating occurs during the day, at night or a combination of the two
  
  
• Whether sweating affects one region (localized) or occurs throughout the skin (generalized)
  
  
• The impact of excess sweating on the patient’s quality of life

Hyperhidrosis can usually be diagnosed by the patient’s history alone. In some instances, an iodine starch test may be performed to outline the exact area of skin affected. The site will be sprayed with a mixture of starch and iodine, which causes the areas that produce sweat to turn black.

If secondary hyperhidrosis is suspected, additional tests may be performed to identify or rule out potential causes of the disorder. These tests may include:

• Thyroid function test. A blood test that may reveal high levels of thyroid hormones (hyperthyroidism).
  
  
• Blood glucose level test. A blood test to check for high blood glucose (hyperglycemia) or diabetes.
  
  
• Urinalysis and imaging tests (e.g., x-ray). These tests may indicate or rule out cancerous cells or tumors as a cause of hyperhidrosis.