Cosmetic Consultation

Optimizing Topical Axillary Control Zoe Diana Draelos, MD

ontrolling axillary perspiration can be a chal- clothing. The need to develop a topical antiperspirant lenge for dermatologists. When perspiration is that controls sweat yet is compatible with and C related to , the challenge is even greater. clothing has led to all of the currently marketed prod- Who would have thought that our armpits could be ucts. This article takes a critical look at topical axillary a mirror of our inner state of repose? While there are perspiration control. many methods for controlling perspiration with oral and injectable neurotoxins, the product Antiperspirants vs most commonly used to control axillary sweating is topi- The words antiperspirant and are sometimes cal antiperspirant. A casual evaluation of the contents of used interchangeably in the common vernacular, but to US Transportation Security Administration–approved the cosmetic chemist these are 2 very different personal carry-on bags of revealed that every bag contained care products. Antiperspirants contain ingredients to a topical antiperspirant of some type. From a sales per- decrease sweating, while deodorants are used solely to spective, topical antiperspirants are a big-volume busi- manage axillary . For this reason, all antiperspirants ness in the United States andCOS usually occupy a half isleDERM can be considered deodorants, but not all deodorants are display in mass merchandisers, such as Target, Walmart, antiperspirants. Table 1 lists the mechanisms for axillary and Walgreens. odor control. Most products currently on the market are Topical antiperspirants are available in a variety of both antiperspirants and deodorants. formulations such as stick, cream, gel, and spray yet the active ingredientDo is an aluminum-containing Not Perspiration Copy and Axillary Odor compound in each of them. The health safety of topical Perspiration is the perfect medium for bacterial growth, antiperspirants has been debated for years. Most recently, which accounts for the axillary odor associated with topical antiperspirants have been linked to can- sweating. Axillary odor is caused by the action of cer in the media but no medical relationship has been on sterile apocrine and eccrine sweat. Apocrine sweat is established. While topical antiperspirants are not to be responsible for a large part of the odor because it is rich worn during breast mammography examinations, the in organic materials. Eccrine sweat, on the other , restriction is not related to breast cancer. The US Food is more dilute and does not provide a high concentra- and Administration expressed some concern in tion of nutrients for bacterial growth. However, eccrine 1978 regarding the long-term inhalation risk of aerosol sweat indirectly promotes axillary odor by dispersing antiperspirants; however, these preparations remain on apocrine sweat over a larger area and providing the the market. moisture necessary for bacterial growth. Axillary also The first antiperspirant, composed of a 25% contributes to odor by acting as a site for apocrine secre- of aluminum chloride hexahydrate in distilled , tions to collect and increases the surface area suitable for was introduced in 1916. This highly effective formula- bacterial proliferation. tion only required application every other day but was Deodorants function either by masking the axillary odor extremely irritating and the low pH level damaged with a or decreasing axillary bacteria growth. Therefore, many deodorants contain antibacterials, such as Dr. Draelos is Consulting Professor, Department of Dermatology, quaternary ammonium compounds (benzethonium chlo- Duke University School of Medicine, Durham, North Carolina. ride) and cationic compounds (chlorhexidine, ). The author reports no conflict of interest in relation to this article. Mechanism for Perspiration Control Correspondence: Zoe Diana Draelos, MD (zdraelos@ Topical antiperspirants reduce axillary moisture by northstate.net). employing aluminum to create a plug within the

110 Cosmetic Dermatology® •MARCH 2010 • Vol. 23 No. 3 Copyright Cosmetic Dermatology 2010. No part of this publication may be reproduced, stored, or transmitted without the prior written permission of the Publisher. Cosmetic Consultation

table 1 table 2 Mechanisms for Axillary Efficacy of Topical Odor Reduction Antiperspirant Formulations

Reduce apocrine secretions Formulation Sweat Reduction, %

Reduce eccrine gland secretions Aerosol 20–33

Remove apocrine and eccrine gland secretions from Cream 35–47 the 15–54 Decrease axillary bacterial colonization Lotion 28–62

acrosyringium to occlude apocrine and eccrine ducts. Roll-on 14–70 Sometimes the aluminum is combined with zirconium Stick 35–40 to enhance efficacy. It takes about 10 days to create the plug, which physically blocks the transport of sweat from the gland onto the skin surface. Conversely, it takes products. These products have a slightly higher con- 14 days for the plug to dissolve. It is for this reason that centration of active ingredient that must reduce sweat the best results with topical antiperspirants are achieved by 30% to substantiate the highly effective claim on the with daily use to maintain theCOS acrosyringeal plug. DERMpackage labeling, but also are recommended for twice- In order for the antiperspirant to work it must physi- daily use. Twice-daily use is actually the key to their cally contact every sweat duct. Even and thorough appli- enhanced efficacy. The antiperspirant must remain in the cation to the entire axillary vault is necessary for optimal axillary vault long enough to form or maintain the plug in results. Some topical antiperspirants have a grid to the acrosyringium. If heavy sweating occurs during appli- encourage even applicationDo and metered dosingNot adminis- cation, Copy the antiperspirant is washed away and rendered tered through turning a knob at the bottom of the appli- ineffective. Because the armpit is generally at rest at night, cator. Using the amount of antiperspirant recommended bedtime application of topical antiperspirants allows the on the package label is important. ingredients to contact the skin longer and create a better acrosyringeal plug that translates into enhanced efficacy. Antiperspirant Efficacy Increased efficacy can be achieved with any topical anti- An efficacious antiperspirant must reduce axillary sweat- perspirant that is used both morning and evening. ing by at least 20%. The degree of sweat reduction is The most effective antiperspirants create a deep plug in determined partly by the formulation. Table 2 lists the the acrosyringium. The more superficial the acrosyringeal efficacy of a variety of currently marketed formula- plug the less sweat control is obtained. Unfortunately, tions. Notice that the efficacy range is broad but overall there is a direct connection between skin irritation and are the least effective and roll-ons are the most acrosyringeal plug depth. Efficacious formulations must effective. This is due to the ability of the product to address both issues to create a skin-friendly product. contact all of the sweat ducts in the axilla to deliver an Some manufacturers include skin-protecting ingredients, optimal dose. such as dimethicone in topical antiperspirant formula- Antiperspirants are considered over-the-counter tions to increase efficacy while counteracting the inherent and thus must follow the rules set forth in the mono- possibility of irritant contact dermatitis. graph covering their formulation. The types of materials that can be incorporated in antiperspirants and their Antiperspirant Failure concentration are carefully controlled by the US Food Antiperspirants can and do fail to meet patient expecta- and Drug Administration. This accounts for the similarity tions for sweat control. As a matter of fact, most of the in formulation by a variety of manufacturers. patients who seek out the help of a dermatologist for the A new category of topical antiperspirants that have purpose of discussing sweat control are antiperspirant been introduced are labeled as “clinical strength” failures. There are a few easy tips that the dermatologist

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might wish to share with patients in need of assistance in you don’t use it, it doesn’t work. Individuals who apply controlling perspiration: topical antiperspirant sporadically will not experience 1. Apply topical antiperspirants to dry armpits—The optimal sweat control. Daily application is necessary for antiperspirant must remain in physical contact with the efficacy, and twice-daily application is even better as pre- acrosyringium long enough to create a plug. If the anti- viously discussed. Consecutive application for 10 days is perspirant is applied to a wet armpit, either wet from necessary to determine the optimal benefit that can be showering or from perspiration, it will be diluted and achieved from a given antiperspirant formulation. not as effective. The armpit can be dried with a hair dryer before antiperspirant application if necessary. Summary 2. Do not shave aggressively—Plugs created in the acro- Topical antiperspirants are the most widely used method syringium can be physically removed by shaving if they for controlling axillary perspiration. Proper application are located close to the skin surface. Individuals who is the key to achieving the best results. Topical antiper- shave repeatedly over the armpit area or shave multiple spirant should be applied liberally to the entire axilla in times daily may notice decreased antiperspirant efficacy. the morning and in the evening to reduce perspiration. It is best to shave the armpits weekly by dragging the In general, roll-on cream products offer the best efficacy razor once over the skin and avoid pulling the skin but care should be taken to apply the dose recommended tight. This minimizes the chance of removing the sweat on the package. Shaving can decrease topical antiperspi- duct plug. rant efficacy by physically removing the plug from the 3. Apply the recommended amount of antiperspirant— acrosyringium. For this reason, aggressive armpit shav- Many topical antiperspirant instructions recommend ing by pulling the skin and shaving repeatedly over the twisting the knob at the bottom of the applicator 3 times skin should be avoided. Finally, compliance is important and applying the dispensed amount to the axilla. This because daily application is necessary to maintain the is the dose needed to obtainCOS optimal efficacy. Encourage DERM acrosyringeal plug. The optimal effect for any antiper- patients to read the instructions and understand that just spirant can only be assessed after 10 consecutive days like medicines that do not work if enough is not ingested, of use. These are a few ideas that dermatologists can antiperspirants also require the proper dose for optimal share with patients in search of better topical axillary efficacy. The recommended amount should be thor- sweat control. oughly massaged throughoutDo the armpit, Notespecially over Copy hair-bearing skin where concentration of sweat is Recommended Reading the greatest. Papa C, Kligman AM. Mechanisms of eccrine anhidrosis. II. the 4. Apply topical antiperspirant daily—Compliance is the antiperspirant effect of aluminum salts. J Invest Dermatol. 1967;49: 139-145. key to many things in medicine, including antiperspirant Holzle E, Kligman AM. Mechanism of antiperspirant action of alumi- efficacy. As with any topical dermatologic treatment if num salts. J Soc Cosmet Chem. 1979;30:279-295. n

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