Classification of Systemic and Localized Sweating Disorders.

Hyperhidrosis can be subdivided into generalized hyperhidrosis, with increased sweating over the entire body, and focal hyperhidrosis, in which the excessive sweating is restricted to specific parts of the body. Generalized hyperhidrosis may be either primary (idiopathic) or secondary. Secondary generalized hyperhidrosis may be caused by infections such as tuberculosis, hyperthyroidism, endocrine and metabolic disturbances such as pheochromocytoma, neurological disorders, or drugs. Focal hyperhidrosis may also be primary (idiopathic) or secondary. Frey's syndrome is one form of secondary focal hyperhidrosis that occurs during eating together with reddening of the area in front of the ear following parotid gland surgery or injury. Primary focal hyperhidrosis is particularly common on the palms and soles of the feet, in the axilla, and on the head. Anhidrosis may be either congenital/genetic or acquired. Some of the most typical forms of congenital/genetic anhidrosis include hypohidrotic ectodermal dysplasia, congenital insensitivity to pain and anhidrosis, and Fabry disease. Acquired anhidrosis is classified as secondary anhidrosis, which may be due to an underlying disorder such as a neurological disorder, an endocrine or metabolic disturbance, or the effect of drugs, or idiopathic anhidrosis for which the pathology, cause, and mechanism are unknown. Idiopathic anhidrosis is classified into acquired idiopathic generalized anhidrosis (AIGA), idiopathic segmental anhidrosis, and Ross syndrome. AIGA is divided into three categories according to differences in the site of disturbance: (1) sudomotor neuropathy, (2) idiopathic pure sudomotor failure, and (3) sweat gland failure.