The predilection for photoaging and skin cancer development to occur more frequently on the left side of the face has been the subject of several hypotheses, with one of the leading hypotheses linking drivers in right-hand-drive cars to greater sun exposure on the left side of the face. Our data did not show a statistically significant difference for lentigines on the left side of the face, which is a distribution pattern that has been previously observed with facial skin cancer distribution.5 This is likely due to the small sample size of the study.
Our study had several limitations. The distribution of the lentigines was plotted by the cosmetic unit, which may result in a loss of information as some subunits covered large surface areas. This was addressed by using a heat map that demonstrated the density in each unit by mapping each individual lentigo. Second, the results of this study were limited to a small population at a single practice in a Boston suburb. The geographic location may result in different sun exposures factors, both with respect to the environment and the patients. As a result, the findings may not be generalizable. Additionally, each lentigo recorded was plotted equally and we did not account for size or degree of pigment of each lentigo.
Our study had several limitations. The distribution of the lentigines was plotted by the cosmetic unit, which may result in a loss of information as some subunits covered large surface areas. This was addressed by using a heat map that demonstrated the density in each unit by mapping each individual lentigo. Second, the results of this study were limited to a small population at a single practice in a Boston suburb. The geographic location may result in different sun exposures factors, both with respect to the environment and the patients. As a result, the findings may not be generalizable. Additionally, each lentigo recorded was plotted equally and we did not account for size or degree of pigment of each lentigo.
CONCLUSION
In this study, lentigines, a marker of photodamage, tended to
be peripherally distributed in the cohort of patients. This data
provides insight into how lentigines are distributed and can help
when counseling patients on sun protective practices such as
sun avoidance, paying particular attention to sunscreen application
on the lateral part of the face, and wearing a broad-brimmed
hat as opposed to shorter brims, or a baseball cap to get more
lateral coverage of the face.
DISCLOSURES
The authors have no conflicts to report.
REFERENCES
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2. Subramaniam P, Olsen CM, Thompson BS, Whiteman DC, Neale RE, for the QSkin Sun and Health Study Investigators. Anatomical distributions of basal cell carcinoma and squamous cell carcinoma in a population-based study in Queensland, Australia. JAMA Dermatol. 2017;153(2):175–182. doi:10.1001/ jamadermatol.2016.4070
3. Richmond-Sinclair, Naomi M, et al. Incidence of basal cell carcinoma multiplicity and detailed anatomic distribution: longitudinal study of an Australian population. J Invest Dermatol. 129(2):323–328
4. Kang KW, Lee DL, Shin HK, Jung GY, Lee JH, Jeon MS. A retrospective clinical view of basal cell carcinoma and squamous cell carcinoma in the head and neck region: A single institution's experience of 247 cases over 19 years. Arch Craniofac Surg. 2016;17(2):56–62. doi:10.7181/acfs.2016.17.2.56
5. Butler ST, Fosko SW. Increased prevalence of left-sided skin cancers. J Am Acad Dermatol. 63(6):1006–1010