Hyperhidrosis, or excessive sweating, is a common disorder that produces a lot of unhappiness. An estimated 2%-3% of Americans suffer from excessive sweating of the underarms (axillary hyperhidrosis) or of the palms and soles of the feet (palmoplantar hyperhidrosis). Underarm problems tend to start around puberty, while palm and sole sweating may begin earlier, often during childhood. Untreated, these problems may continue throughout life.

Pictured is an example of the starch-iodine test in the left axilla. Mote the prominent dark blue-black discoloration at sites of hyperhidrosis.