What is the term for the deficiency in perspiration, often resulting from fever or certain skin diseases?

Anhidrosis is the medical term used to describe a deficiency in perspiration. This condition can occur due to several reasons, including fever or specific skin diseases that affect the body's ability to sweat. Sweating is essential for thermoregulation and maintaining the body's core temperature. When an individual experiences anhidrosis, they may be unable to cool down adequately, which can lead to overheating and other complications.

In contrast, hyperhidrosis refers to excessive sweating, which is the opposite of anhidrosis. Hydrosis is not a commonly used term in medical contexts, thus not applicable in this scenario. Dehydration relates to a deficiency in body fluids, which can also affect perspiration but is not specifically a term for the inability to sweat.

Anhidrosis directly addresses the issue of insufficient perspiration, making it the correct choice for this question. The other terms do not accurately capture the lack of sweat production that is central to the inquiry.