By Abby S. Van Voorhees, MD, August 01, 2014
In this month’s Acta Eruditorum column, Physician Editor Abby S. Van Voorhees, MD, talks with Loretta Davis, MD, about her recent JAMA Dermatology article, “Further Investigation Into the Risk of Skin Cancer Associated With the Use of UV Nail Lamps.”
Dr. Davis: After a JAMA Dermatology case report described squamous cell carcinoma on the hands of two women who had frequently used nail lamp devices, concern for safety was raised. Subsequent studies showed that these devices mainly emit UVA similar to tanning beds but at much smaller levels. Other researchers used mathematical models to show that a subject is only exposed to a small amount of UVA and thus the risk for carcinogenesis is relatively small. However, until our study, no one had performed random samplings of UV light exposure from actual devices in salons.
Based on our study, we found that clients receive only a small amount of ultraviolet light with each treatment and thus the skin cancer risk per visit is very small and likely remains small with even multiple exposures. However, the in vivo risk for an individual over a lifetime has yet to be measured.
The topic has been controversial and more studies need to be performed. However, all the medical based studies to date have shown a low risk for skin cancer development.
Dr. Van Voorhees: Tell us about your study. What specifically did you look at and what did you find?
Dr. Davis: We performed a random sampling of 17 nail lamps in 16 different salons. We used a light meter that measures light in the wavelength range of both UVA and UVB, specifically 280-400 nm. We measured the irradiance in the different devices in five different locations within the device. We then calculated the energy that one’s hand would receive while using the device in one treatment. Next, we calculated the number of visits per device that it would take to reach a point that may induce damage to the skin. The point we used was 60J/cm2 which is an energy that has been shown to induce DNA damage in keratinocytes. Finally, assuming a person on average goes to the salon once every three months, which may be an underestimation, we then calculated the number of months it would take a person to reach this threshold.
We found that the amount of UV energy emitted by these devices is quite small; therefore, one can assume there is only a minor risk to the user. [pagebreak]
Dr. Van Voorhees: Did the units emit only UVA? Were other wavelengths of light identified such as UVB wavelength light?
Dr. Davis: We used a light meter which measured wavelengths encompassing both UVA and UVB. However, similar to previous studies, we found that the devices emitted mainly UVA.
Dr. Van Voorhees: Given the output of these units and the time of exposure to the skin of the digits do you feel that DNA damage is occurring in the skin secondary to the lamp exposures? What else did you find?
Dr. Davis: Based on the results of our study, we can only assume that DNA damage occurs once a person has received enough UV energy to reach the threshold of 60J/cm2. One very important point that our study highlights is the fact that the lights we measured emitted a wide range of energy. For example in table 1, light #2 emitted almost no measurable energy compared to light #11. Therefore, one would have a higher risk of skin damage from light #11 compared to light #2.
Dr. Van Voorhees: Did you limit your study to salons? Did you look at findings for home units?
Dr. Davis: Our study was limited to salons and did not include home units. It would be important to look at home units in future studies.
Dr. Van Voorhees: Is there an upper limit to the number of nail manicure visits that we should be recommending for our patients? Other recommendations?
Dr. Davis: That is a difficult question to answer. The answer to this question lies in the specific device being used, and this is something that neither you or your patient will know unless it is specifically measured. We found a wide range of wattage in the bulbs in these devices and showed that higher wattages correlated with higher UV energy exposure. Therefore, the recommended number of visits would be based on the individual device and would have to fall under the number determined to reach the threshold for DNA damage.
So, while there is a small risk with each exposure, there will be individuals who put themselves at increased risk by visiting nail salons monthly or even weekly ultimately reaching the threshold for DNA damage.
Therefore, we strongly recommend the routine use of UV protection in the form of gloves with only the nails exposed and/or sunscreen. Dr. Davis is professor and chief of dermatology at Georgia Regents University. Her article was published online on April 30 by
JAMA Dermatology. JAMA Dermatol. Published online April 30, 2014. doi:10.1001/jamadermatol.2013.8740.