The main secretory function of the skin is performed by the sweat glands, which help to regulate body temperature. These glands excrete perspiration that evaporates, thereby cooling the body. The sweat glands are located in various parts of the body and re-spond to different stimuli. Those on the trunk generally respond to thermal stimulation; those on the palms and soles respond to nervous stimulation; and those in the axillae and on the forehead respond to both kinds of stimulation. Normal perspiration has no odor. Body odor is produced by the increase in bacteria on the skin and the interaction of bacterial waste products with the chemicals of perspiration.
As a rule, moist skin is warm, and dry skin is cool, but this is not always true. It is not unusual to observe warm, dry skin in a dehydrated patient and very hot, dry skin in some febrile states.
Normally, sweat can be controlled with the use of antiperspi-rants and deodorants. Most antiperspirants are aluminum salts that block the opening to the sweat duct. Pure deodorants inhibit bacterial growth and block the metabolism of sweat; they have no antiperspirant effect. Fragrance-free deodorants are available for those with sensitive skin (Odom et al., 2000).