Focal Hyperhidrosis

This pattern usually affects both sides of the body evenly and often begins earlier in life. Because the sweating is localized, people frequently notice it most in situations involving those particular areas, such as handshakes or writing. It is the typical distribution seen in the primary form of hyperhidrosis. The focused nature helps distinguish it from generalized sweating that spreads more widely. More than one focal area can be involved at once, so sweaty palms and soles often occur together. A visual test that stains sweaty skin can help map exactly where the focal sweating is heaviest. The word focal simply means limited to a specific spot or region. The affected areas tend to be those richest in eccrine glands. Because these areas are often involved in daily contact, the sweating can feel especially disruptive.

Heavy sweating limited to the hands and feet, while the back stays dry, illustrates the focal pattern. Someone might find that their palms and soles both sweat noticeably in the same situations, since these focal areas frequently occur as a pair. A person whose underarms soak through shirts but whose legs stay dry shows the same localized distribution in a different region.

It describes the distribution seen in primary hyperhidrosis, includes palmar, plantar, axillary, and craniofacial forms, and can be mapped with the starch-iodine test.