Uncovering the cause of armpit irritation

Q.Why do antiperspirant/deodorants cause skin irritation?

A. Antiperspirants and not deodorants are the culprit in skin irritation. The antiperspirant decreases sweating while the deodorant simply provides a pleasant scent to the armpit.

The active ingredient in all widely marketed antiperspirants is an aluminum salt possibly mixed with a zirconium salt. The aluminum salt is very irritating to the skin, especially in high concentration. As a matter of fact, the aluminum salt functions to decrease the release of perspiration from the armpit by coagulating protein in the eccrine and apocrine sweat ducts, and it may also coagulate the stratum corneum protein lining the armpit as well. More modern antiperspirant formulations minimize this irritation by incorporating dimethicone, listed on the skin protectant monograph.

For patients that experience irritation from antiperspirant/deodorants and wish to continue using these products, it is possible to offer some advice. The antiperspirant/deodorant should be applied at night since the armpit is at rest with less sweat and will work better. In the morning, a thin dimethicone-based moisturizer could be applied to the armpit. This provides a compromise between sweat reduction and skin irritation.

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