Primary or focal hyperhidrosis may be further divided by the area affected, for instance, palmoplantar hyperhidrosis (symptomatic sweating of only the hands or feet) or gustatory hyperhidrosis (sweating of the face or chest a few moments after eating certain foods).Hyperhidrosis can also be classified by onset, either congenital (present at birth) or acquired (beginning later in life). Primary or focal hyperhidrosis usually starts during adolescence or even earlier and seems to be inherited as an autosomal dominant genetic trait. It must be distinguished from secondary hyperhidrosis, which can start at any point in life. Secondary hyperhidrosis may be due to a disorder of the thyroid or pituitary glands, diabetes mellitus, tumors, gout, menopause, certain drugs, or mercury poisoning.One classification scheme uses the amount of skin affected. In this scheme, excessive sweating in an area of  100 square centimeters (16 square inches) or more is differentiated from sweating that affects only a small area.Another classification scheme is based on possible causes of hyperhidrosis. Causes
The cause of primary hyperhidrosis is unknown. Anxiety or excitement can exacerbate the condition. A common complaint of patients is they get nervous because they sweat, then sweat more because they are nervous. Other factors can play a role, including certain foods and drinks, nicotine, caffeine, and smells. Similarly, secondary (generalized) hyperhidrosis has many causes including certain types of cancer, disturbances of the endocrine system, infections, and medications. Primary
Primary (focal) hyperhidrosis has many causes.
Procedures
Injections of botulinum toxin type A can be used to block neural control of sweat glands. The effect can last from 3–9 months depending on the site of injections. This use has been approved by the U.S. Food and Drug Administration (FDA). The duration of the beneficial effect in primary palmar hyperhidrosis has been found to increase with repetition of the injections. The Botox injections tend to be painful. Various measures have been tried to minimize the pain, one of which is the application of ice. This was first demonstrated by Khalaf Bushara and colleagues as the first nonmuscular use of BTX-A in 1993. BTX-A has since been approved for the treatment of severe primary axillary hyperhidrosis (excessive underarm sweating of unknown cause), which cannot be managed by topical agents.A microwave-based device has been tried for excessive underarm perspiration and appears to show promise.Tap water iontophoresis as a treatment for palmoplantar hyperhidrosis was originally described in the 1950s. Studies showed positive results and good safety with tap water iontophoresis. One trial found it decreased sweating by about 80%. Surgery
Sweat gland removal or destruction is one surgical option available for axillary hyperhidrosis (excessive underarm perspiration). There are multiple methods for sweat gland removal or destruction, such as sweat gland suction, retrodermal curettage, and axillary liposuction, Vaser, or Laser Sweat Ablation. Sweat gland suction is a technique adapted for liposuction.The other main surgical option is endoscopic thoracic sympathectomy (ETS), which cuts, burns, or clamps the thoracic ganglion on the main sympathetic chain that runs alongside the spine.