Anhidrosis means not sweating. This word is from the Greek an – meaning a lack of + hidros meaning sweat = lack of sweat. The inability to sweat may seem a blessing but it is not, since to sweat is to be able to stay cool. Anhidrosis creates a dangerous inability to tolerate heat.
Anhidrosis sometimes goes unrecognised until a substantial amount of heat or exertion fails to cause sweating. Overall lack of sweating can be life threatening because the body will overheat. If the lack of sweating is localised, it is usually not as dangerous.
Common causes are -
neurologic disorders such as Guillain-Barre syndrome
skin diseases that block sweat glands
congenital disorders including as ectodermal dysplasia
trauma to sweat glands
If there is a danger of overheating, it is advisable to take a cold shower or sit in a cool bathtub and drink plenty of fluids. Remain in a cool environment. Move slowly during hot weather. Avoid heavy exercise and hot foods.