hyperhidrosis / excessive sweating

Introduction

hyperhidrosis is chronic and excessive sweating to the extent that patients sweat so profusely that they have to change their clothes several times a day
emotional sweating is mediated by cortical–limbic activation that signals to preganglionic sympathetic neurons in the spinal cord, which synapse onto cholinergic postganglionic neurons releasing acetylcholine onto eccrine sweat glands
in contrast, thermoregulatory sweating originates in hypothalamic preoptic nuclei in response to core temperature changes
botulinum toxin blocks the nerve signals that stimulate sweat production and can be used to treat excessive sweating

primary idiopathic hyperhidrosis:
- affects an estimated 2 to 5 per cent of the population
- typically affects the palms, soles, and axillae and is often triggered by emotional stimuli
- frequently accompanied by anxiety and other dysautonomic symptoms
- 2/3rds report a positive family history, and the early age of onset and inheritance patterns suggest a Mendelian genetic basis
- genetic:
  - defects in a specific neuronal protein channel - the Nav1.8 ion channel which results in the ion channel remaining excessively open causing the sweat glands to be constantly overstimulated¹⁾
secondary hyperhidrosis
- physiological transitions eg. adolescence
- systemic illness
- drug-induced effects

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