When we touch a client, what are we exposing ourselves to? What happens when someone who uses a medication designed to be absorbed through the skin gets a massage? Are massage therapists unknowingly picking up unintended doses?

To help me address this question, I partnered with Annie Morien, PhD, massage therapist, and dermatology expert, who has clarified some of the finer points of the interactions between skin applications of medicine and massage therapists’ hands.

Here is a paraphrase of the communication that got this all started:

“I work in a massage franchise where I see several people every day and the turnover is quick. We take a health history, but it’s pretty brief—it’s just to make sure everybody is safe. A couple of days ago, I had a client who, halfway through the massage, told me she had just started using a hormone cream to help with symptoms of menopause. She applied it every day to her thigh—which is exactly where I was working at that moment. I didn’t say anything at the time, but do I have to worry about excess estrogen exposure now?”

Many health-care products are applied to the skin instead of taken by mouth. These can include essential oils, hormones, and prescription pain relievers, among many others. People may use one or more of these products before they arrive for a massage appointment. Since these products are designed to be absorbed by the primary user, we have to wonder whether massage therapists could absorb them as well. To explore this possibility, first we will review the skin’s ability to block absorption, then we will look at some research behind skin-to-skin transference: the unintentional absorption of another person’s topical medication.

Skin: A Natural Barrier

Our skin forms an excellent barrier to the outside world, maintaining the integrity of our internal environment while limiting absorption. It accomplishes this task at several levels. The first functional barrier is the most superficial layer, the stratum corneum. It contains a complex arrangement of keratinocytes (dead skin cells that have been filled with waterproofing keratin), lipids, proteins, and cementing materials. When we develop a callous on our hands or feet, it is the stratum corneum that thickens. This layer also blocks penetration of most substances into deeper layers, while retaining skin hydration. Deep to the stratum corneum, several other epidermal layers contain the skin’s sensory and immune cells. Sensory cells detect touch, temperatures, pressure, and pain, thus alerting us to possible skin injury and pathogenic invasion. 

The thickness of the epidermis is quite consistent across most body areas. Hands and feet have an extra layer, the stratum lucidum, which offers protection from sheering forces and friction. The stratum lucidum may also help with protection from absorption by being an extra barrier. By contrast, the thickness of the dermis and adipose layers of the skin varies greatly across body areas, and by age and gender; skin thickness over the eyelid is very thin compared to skin over the abdomen, for instance. Infants and elders have thinner skin compared to adults.¹ Men have thicker skin compared to women, although no evidence that this influences barrier function has been found.

As functional as it is, skin is not completely impermeable. The stratum corneum limits absorption of most substances, but some compounds are able to penetrate through the epidermis to various skin depths. For example, most sunscreens are designed to remain within the upper epidermis so that they can block or absorb ultraviolet rays. However, some topical prescription and nonprescription medications are designed to pass through the epidermis and enter the circulatory capillaries that lie just beneath. This property is called transcutaneous absorption.

Transcutaneous Absorption

Molecular size, chemical properties, and the specific chemical mixture influence the efficiency of transcutaneous absorption. Small molecules move through the layers of the skin more easily than large ones, just as some chemical properties allow substances to pass into and through the skin’s lipid layer more easily than others. Transcutaneous absorption is also assisted by particular mixtures of chemicals (as seen in essential oils), as well as the presence of special enhancer chemicals. 

Skin characteristics also influence the efficiency of absorption. Areas with many hair follicles allow more passageways for substances to penetrate into skin and access the blood vessels. Areas where the skin is relatively thin allow for greater absorption compared to thick skin. Compromised skin—as seen with the pathologically dry skin of eczema, ichthyosis, and psoriasis—is also more easily penetrated by chemical compounds because the epidermis lacks the sealant qualities found in healthy skin. 

Topical Applications

Manufacturers make gels, lotions, patches, and sprays that enhance transcutaneous absorption. The appeal of these is threefold: increased convenience, fewer side effects, and improved compliance. Some amount of medication is absorbed through the skin and directly into the bloodstream, thus bypassing the liver and gastrointestinal system. This decreases liver toxicity, stomach and intestinal complaints, and related side effects. It may also allow medications to work faster. 

When a topical medication is applied via a patch, it is easy to identify. This is a delivery system that is frequently used for nicotine, nitroglycerin, and birth control, and products are in development for many other types of medications. Patches show obvious boundaries for where the medication is active, but when the medicine is applied without any identifying marker, it’s impossible to know it is there. This unintentional absorption may be an issue for massage therapists.

Unintentional Hormone Absorption

Both men and women commonly use topical hormone preparations. For women, this hormone combination typically includes estrogen and progesterone, which can serve as a form of birth control or can ease menopausal symptoms. Androgen preparations (testosterone and related derivatives) serve to enhance masculine features for men.  

But what is the risk of skin-to-skin transference of a hormone preparation? We know that some proportion of medicine is absorbed into the skin while some remains on the surface. Several studies suggest skin-to-skin transference does, in fact, occur. For example, when women have short-term contact (one week) with male partners’ testosterone-treated skin, the women exhibit elevated blood testosterone levels.² With prolonged contact (months to years), women may have significant physical changes, such as acne, a deepened voice, facial hair growth, hair loss, genital changes, and muscle hypertrophy.³ 

In some men, contact with topical estrogen caused elevated blood estradiol levels.⁴ However, no significant physical changes were reported in these studies. 

Other studies report that children show early sexual development and bone growth changes after prolonged exposure to topical testosterone.⁵ Children who have months to years of contact with topical estrogen show changes in breast and genital development.⁶ In children and adults, most adverse effects reverted back to normal within months after cessation of physical contact with hormone-treated skin.

It is important to note that hundreds of thousands of people use topical hormone preparations, and relatively few negative consequences are reported. Of those cases of adverse physical changes, most resulted because patients failed to follow medical directions intended to protect against skin-to-skin transference. These directions include covering the treated area, avoiding skin-to-skin contact with others, and washing the treated area if contact is made.

What Can a Massage Therapist Do?

Obviously, it is preferable not to be exposed to topical medication, especially when pregnant. The good news is that if contact is made with a client’s topical hormones during a massage session, it is likely the amount absorbed would be extremely low because of the short contact time. Risk is further decreased when the massage therapist immediately washes his or her hands and forearms after the session. Clients can help decrease the risk of skin-to-skin transference if they wash the treated area or cover the affected skin beforehand. Massage therapists are advised to follow these commonsense precautions: 

1. Ask the client about medication use, and be sure to include topical medications within that discussion. 

2. If topicals are used, find out how recently each dose was applied. In general, the more time that has passed since application, the better. 

3. Avoid directly touching the area treated with topical medications. Cover the area, if possible. A good general rule is to avoid the skin within several inches of the treated area.

4. Wash hands and forearms immediately after the massage. 

5. Gloves may offer some protection, but the level of protection depends on the substance in question. Some topical medications may penetrate gloves, so don’t count on these to keep you safe all the time. 

Safe, appropriate skin-to-skin contact within massage therapy is one of the qualities that makes this profession unique within the health-care field. Unfortunately, it also carries some unique occupational hazards. Accidental exposure to topical medications is a small but not inconsequential risk that can be easily avoided with simple precautions—starting with good communication between the therapist and the client. 

  Ruth Werner is a writer and educator approved by the National Certification Board for Therapeutic Massage & Bodywork as a provider of continuing education. She
wrote A Massage Therapist’s Guide to Pathology
(Lippincott Williams & Wilkins, 2012), now in its fifth edition, which is used in massage schools worldwide. Contact her at www.ruthwerner.com or wernerworkshops@ruthwerner.com.

Notes

1. G.N. Stamatas et al., “Infant Skin Microstructure Assessed In Vivo Differs from Adult Skin in Organization and at the Cellular Level,” Pediatric Dermatology 27, no. 2 (2010): 125–31; P.M. Elias and R. Ghadially, “The Aged Epidermal Permeability Barrier: Basis for Functional Abnormalities,” Clinics in Geriatric Medicine 18, no. 1 (2002): 103–20.

2. J. Stahlman et al., “Serum Testosterone Levels in Non-Dosed Females after Secondary Exposure to 1.62% Testosterone Gel: Effects of Clothing Barrier on Testosterone Absorption,” Current Medical Research & Opinion 28, no. 2 (2012): 291–301.

3. A.S. Kathiresan et al., “Virilization from Partner’s Use of Topical Androgen in a Reproductive-Aged Woman,” American Journal of Obstetrics & Gynecology 205 no. 3 (2011): e3–4; W. de Ronde, “Hyperandrogenism After Transfer of Topical Testosterone Gel: Case Report and Review of Published and Unpublished Studies,” Human Reproduction 24, no. 2 (2009): 425–8; C.M. Ogilvie et al., “Bioidentical Testosterone Cream: A Rare Cause of Postmenopausal Virilisation,” The Australian and New Zealand Journal of Obstetrics and Gynaecology 49, no. 1 (2009): 116–7. 

4. R.J. Schumacher et al., “The Effects of Skin-to-Skin Contact, Application Site Washing, and Sunscreen Use on the Pharmacokinetics of Estradiol from a Metered-Dose Transdermal Spray,” Menopause 16, no. 1 (2009): 177–83; M.B. Taylor and M.J. Gutierrez, “Absorption, Bioavailability, and Partner Transfer of Estradiol from a Topical Emulsion,” Pharmacotherapy 28, no. 6 (2008): 712–8.

5. A. Mason et al., “Sexual Precocity in a 4 Year Old Boy,” British Medical Journal 340 (2010): c2319; C. Brachet et al., “Children’s Virilization and the Use of a Testosterone Gel by their Fathers,” European Journal of Pediatrics 164, no. 10 (2005): 646–7; Food and Drug Administration Pediatric Advisory Committee, “Review of Pediatric AERS Reports of Secondary Testosterone Exposure Associated with AndroGel Topical Testosterone,” accessed July 2012, www.fda.gov/downloads/AdvisoryCommittees/CommitteesMeetingMaterials/PediatricAdvisoryCommittee/UCM166691.pdf.

6. S.L. Franklin, “Effects of Unintentional Exposure of Children to Compounded Transdermal Sex Hormone Therapy,” Pediatric Endocrinology Reviews 8, no. 3 (2011): 208–12.