 An extreme case of hypohydrosis in which there is a complete absence of sweating and the skin is dry is termed anhidrosis.Sweat is readily visualized by a topical indicator such as iodinated starch (Minor test) or sodium alizarin sulphonate, both of which undergo a dramatic colour change when moistened by sweat.A thermoregulatory sweat test can evaluate the body’s response to a thermal stimulus by inducing sweating through a hot box ⁄ room, thermal blanket or exercise.