Antiperspirant May Prevent Foot Blisters

In a double-blind study, cadets attending the U.S. Military Academy were separated into two groups that used either an antiperspirant or a placebo preparation. Each group was asked to apply the preparation for five consecutive nights before completing a 21-km hike. After the hike, only 21 percent of the cadets who reported using the preparation for at least three nights before the hike were diagnosed with foot blisters. The placebo group reported a 48 percent incidence of foot blisters.

"Blisters are usually minor problems, but they can cause great discomfort for the patient," said Joseph J. Knapik, ScD, the lead author of the study that appeared in the August 1998 issue of the Journal of the American Academy of Dermatology. "Typically they only require simple first aid and a short period of limited activity. It is possible, however, for them to lead to more serious problems such as local or systemic infections." -more-

Blisters are caused by rubbing moist skin that results in higher frictional forces than rubbing very dry skin. Foot blisters are one of the most common injuries an active person can experience. Researchers theorized that reducing sweating might reduce friction and consequently reduce blisters. The cadets applied the preparation to completely dry feet, up the ankle to the top of the boot line. Before the hike, each cadet was examined for existing foot conditions. Immediately after the hike, the feet of each cadet were inspected for blisters using the same criteria as the pre-hike examination. Researchers found that sweat reduction was a key mechanism for the reduction of blisters. While the antiperspirant was found to be very effective in reducing blisters, some side effects did occur. "Itching and rashes occurred in 57 percent of the antiperspirant group, but only six percent of the placebo group," Dr. Knapik stated. "This suggests that a large portion of the population may have problems with the antiperspirant used in the study. However, reducing the amount of the active compound or applying the antiperspirant every other night, rather than every night as the cadets did, may reduce the irritation."

The American Academy of Dermatology is the largest and most influential society representing physicians who specialize in treating skin, hair, and nail conditions.