What is excessive sweating or hyperhidrosis?

Hyperhidrosis or excessive sweating, is when the body sweats in excess of what it needs to maintain a normal body temperature. The most commonly affected areas are the underarms, palms and soles but it can affect any body site. Excess sweating can be caused by a variety of factors; they can be genetic or triggered by factors like heat, spicy food, stress, or illness.