How to Stay Safe in the Summer Sun

With the summer in full swing, patient education hasaligned itself with anticipated ailments related to sun exposure. Thankfully, there are several protective measures that only require a little forethought, such as packing extra sun-screen and fluids for a day outside in the heat.

It is important to first acknowledge that sun protection should be regarded year-round. Clinical and epidemiological evidence shows that malignant melanoma—the deadliest form of skin cancer—is seen in patients who have experienced repeated intense exposuren to sunlight.¹This implies that sunlight in the summer months alone is not the only factor at play. In fact, ultraviolet (UV) radiation levels can be high even on cloudy days.²

UV Radiation

This is responsible for sunburn, photoaging, and skin cancer. Five percent of UV radiation is called UV-B,³which causes sunburn, hyperpigmentation, and skin cancer. The rest of UV radiation is called UV-A; of this type, UV-A1 (long wavelength) is less potent than its counterpart, UV-A2 (short wave-length), which can have detrimental effects similar to UV-B. In the continental United States, the hours between 10am and 4pm present the most dangerous UV exposure.⁴

Repeated or extensive exposure to sunlight is a definite risk factor for melanoma.⁵Tanning bed use, especially before age 35, also increases melanoma risk.⁶Notably, exposure to UV radiation is the most important risk factor for basal cell skin carcinoma (BCC). Cutaneous squamous cell carcinoma (SCC) is less common on non-sun exposed areas of the skin, while sunexposed sites are the most common locations for SCC.⁷

The global incidence of malignant melanoma continues to rise and is increasing faster than any potentially preventable cancer in the United States.^8-10

Of the non-melanoma skin carcinomas, the majority of the rest are BCC, according to the American Cancer Society. Moreover, there appears to be a high prevalence of non-melanoma skin cancer in the United States.¹¹

Sunscreen

These contain filters to reflect or absorb UV radiation. In 2011, the FDA administered guidelines for labeling sunscreen products. Now, only sunscreens that pass the FDA’s test for protection against both UV-A and UV-B radiation can be labeled “broad spectrum.” Furthermore, only products that meet FDA standards and are at least SPF 15 can be designated as those that decrease the risks of skin cancer and photo aging. The FDA also mandated that sun protection factor (SPF) be capped at 50 and sunscreens with a higher SPF be labeled as “50+.”¹²

A sunscreen termed “water-resistant” means the SPF is maintained for 40 minutes of water activity. Very water-resistant” implies 80 minutes. The FDA has expunged all labels of “sweat-proof” and waterproof.”¹²

Sunscreens are typically formulated with organic and inorganic filters. The former absorbs UV and converts it to heat. Avobenzone is an example of an organic filter. Inorganic filters, such as zinc ide and titanium dioxide, reflect and scatter UV light. Inorganic sunscreens are generally more stable and have low irritating and sensitizing potential. This type also offers broad-spectrum against both UV-A and UV-B. The combination of both organic and inorganic filters affords maximum efficacy against the entire UV spectrum.¹³

SPF is often a confusing concept for the average patient because the relationship between SPF and protection is not linear. The notion that SPF 30 is twice as effective as SPF 15 is a myth that may need explaining to the patient. When properly applied, a sunscreen with SPF 15 protects the skin from 93% of UV-B radiation, while SPF 30 provides 97% protection.¹³

All individuals, regardless of skin phototype, are subject to the adverse effects of UV radiation. Subsequently, everyone can benefit from sunscreen use. However, light-skinned individuals are more susceptible to both chronic and acute skin changes from skin exposure, and thus they reap the most benefit from routine SPF product use. In response to the question, “Who needs sunscreen?”, the American Academy of Dermatology (AAD) states, “Everyone.”¹⁴

Key words for the astute clinician to impart on patients are “repeatedly” and “liberally.” Sunscreens must be applied in this fashion to be protective. Timing is also important, and sunscreens should be applied 15 to 30 minutes ahead of planned sun exposure to allow time for maximum absorption. Then, reapplication is necessary every 2 hours. All sunscreens wash off with swimming and sweating, and despite a label of “water-resistance,” products still need to be reapplied.¹³

To achieve the full SPF value, 2 mg/cm of sunscreen is needed, which is approximately the amount required to fill a 1-oz (30-mL) shot glass. It has been reported that most patients do not apply a sufficient amount of sunscreen in order for it to be effective; hence, SPF30 or more, instead of SPF 15, is recommended for adequate protection.¹⁵Accordingly, the AAD recommends broad-spectrum protection with SPF 30 or higher and water resistance.¹⁴

One of the most profound benefits of diligent sunscreen use is the prevention of skin cancer. Regular use of sunscreen has been found to reduce the incidence of malignant melanoma.¹⁶Strong evidence exists that sunscreens prevent the development of actinic keratoses and SCC.^17,18Study results have also shown a statistically insignificant reduction in BCC incidents with sunscreen use.¹⁷

Sunscreen may prevent chronic skin photo damage or photo aging, and thus pigmentation and wrinkling, as well as photodermatoses.¹⁹Rarely, sunscreens can elicit an allergic reaction or contact dermatitis. Nevertheless, they are generally very effective in photo protection when applied appropriately.

Other Sun Barriers

Other methods of sun protection are barriers such as clothes, hats, and sunglasses. Tightly woven fabric is more effective in protecting skin, and a dry shirt is more effective than a wet one. Darker colors are also generally better than lighter ones in protecting individuals from the sun. The Skin Cancer Foundation has formulated a list of recommended sun protection products and, further, has designated new Seals of Recommendation, which are bro- ken down into those for daily use, and those for active use. A product finder search is available through this foundation that relays the product’s SPF and the seal it was granted.²⁰

Sunglasses are highly advisable to protect eyes and reduce cataract risk, as well as prevent periorbital skin dam- age. Recommend that patients choose sunglasses that block UV-A and UV-B rays. Most sunglasses sold in the United States meet this standard.⁴

Another important yet simple barrier about which to remind patients is shade. However, shade is likely insufficient alone to protect from the sun, so concomitant sunscreen is advisable.

Hydration

Although the human body remains remarkably resilient in the cold, it cannot tolerate temperatures many degrees above normal. Heat-related illness is a concern for all those who spend time in the warm outdoors, and it is an even more profound danger for athletes and outdoor laborers. Proper hydration is paramount to staying safe in the sun.

The CDC has reported an increase in the trend of exertional heat illness in the United States. There was a reported average of 9237 cases of exertional heat illness among high school athletes per year from 2005 to 2009.²²

Risks factors for heat illness include the following:

• high ambient temperature

• high humidity

• strenuous exercise

• lack of acclimatization

• obesity

• physical deconditioning

• certain drugs such as antihistamine, decongestants, beta-blockers, diuretics, anticholinergics, anti- epileptics, tricyclic antidepressants, lithium

• alcohol intake

Patient education should include warning signs for heat illness, which include lightheadedness, fatigue, flushed skin, decreased appetite, thirst, muscle cramps, and dark-colored urine.²³

The American College of Sports Medicine (ACSM) suggests 16 to 20 oz. of fluid 1 to 2 hours before outdoor activity and 6 to 12 oz. of fluid every 15 minutes, once the individual is outside. Another 2 to 3 cups (16—24 oz.) after returning from outside is recommended afterward, as well.²³Generally speaking, it is important to advise patients to drink before, during, and after outdoor activities.

For athletes exercising in hot temperatures, the ACSM states that “matching fluid intake with water lost through sweat is one of the most critical factors in preventing heat illness.” They instruct athletes to consume at least half of their body weight in ounces 20 minutes before exercising and another 8 to 10 oz every 15 minutes during practice.²⁴Again, rehydrating after the workout is important.

If exertion is not at high levels and an individual intends to be out in the sun and heat for 1 hour or less, a liberal amount of water generally suffices to maintain hydration. However, should activity be more aggressive or last longer than 60 minutes, then sports drinks are the recommended choice for prevention of dehydration. Most sports drinks offer a mix of sugars (such as glucose, sucrose, or fructose) plus electrolytes and, most importantly, sodium; most are isotonic in that they have a similar concentration of salt and sugar as the human body.^25,26

On the contrary, available fitness waters do not typically offer significant carbohydrates, which, if depleted during vigorous exercise, are necessary to replace. Fitness waters do, nonetheless, have fluids to help maintain hydration.

It is important for patients to understand that drinks such as alcohol, and caffeinated beverages, such as tea, coffee, and colas, are not recommended for hydration purposes. Each of these tends to instead pull water from the body and induce dehydration. Fruit juices also tend to be heavier in carbohydrates and low in sodium and, as such, are not ideal for rehydration.

References

1. US Department of Health and Human Services. The Surgeon General’s call to action to prevent skin cancer. US Department of Health and Human Services, Office of the Surgeon General, Washington, DC, 2014.
2. World Health Organization. Ultraviolet radiation: global solar UV index. WHO website.who.int/uv/resources/archives/fs271/en/. Accessed May 12, 2016.
3. de Gruijl FR, Rebel H. Early events in UV carcinogenesis--DNA damage, target cells and mutant p53 foci.Photochem Photobiol.2008;84(2):382-387.doi: 10.1111/j.1751-1097.2007.00275.x.
4. CDC.gov. Don’t get burned! Summer sun safety tips. CDC website.cdc.gov/media/subtopic/matte/pdf/summer_burned.pdf. Accessed June 16, 2016.
5. Elwood JM, Jopson J. Melanoma and sun exposure: an overview of published studies.Int J Cancer.1997;73(2):198-203.
6. International Agency for Research on Cancer Working Group on artificial ultraviolet (UV) light and skin cancer. The association of use of sunbeds with cutaneous malignant melanoma and other skin cancers: A systematic review.Int J Cancer.2007;120(5):1116-1122.doi: 10.1002/ijc.22453.
7. Gloster HM Jr, Neal K. Skin cancer in skin of color.J Am Acad Dermatol.2006;55(5):741-760.
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9. Kohler BA, Sherman RL, Howlader N, et al. Annual Report to the Nation on the Status of Cancer, 1975-2011, Featuring Incidence of Breast Cancer Subtypes by Race/Ethnicity, Poverty, and State.J Natl Cancer Inst.2015;107(6):djv048.doi: 10.1093/jnci/djv048.
10. American Cancer Society Cancer Facts and Figures 2010.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-026238.pdf.Accessed May 12, 2016.
11. Stern RS. Prevalence of a history of skin cancer in 2007: results of an incidence-based model.Arch Dermatol.2010;146(3):279-282.doi: 10.1001/archdermatol.2010.4.
12. FDA sheds light on sunscreens. FDA website.fda.gov/forconsumers/consumerupdates/ucm258416.htm.Accessed May 12, 2016.
13. Baron ED. Selection of sunscreen and sun-protective measures. UpToDate website. uptodate.com/contents/selection-of-sunscreen-and-sun-protective-measures?source=machineLearning&search=sunscreen&selectedTitle=1~150§ionRank=2&anchor=H11208302#H9424613. Accessed May 12, 2016.
14. American Academy of Dermatology. Sunscreen FAQs. AAD website.aad.org/media/stats/prevention-and-care/sunscreen-faqs.Accessed May 12, 2016.
15. Cancer Council Australia. Preventing skin cancer. Cancer Council Australia website.cancer.org.au/cancersmartlifestyle/SunSmart/Preventingskincancer.htm.Accessed May 12, 2016.
16. Hackenberg S, Kleinsasser N. Dermal toxicity of ZnO nanoparticles: a worrying feature of sunscreen?Nanomedicine (Lond). 2012;7(4):461-463.doi: 10.2217/nnm.12.23.
17. van der Pols JC, Williams GM, Pandeya N, Logan V, Green AC. Prolonged prevention of squamous cell carcinoma of the skin by regular sunscreen use.Cancer Epidemiol Biomarkers Prev.2006;15(2):2546-2548.
18. Darlington S, Williams G, Neale R, Frost C, Green A. A randomized controlled trial to assess sunscreen application and beta carotene supplementation in the prevention of solar keratoses.Arch Dermatol.2003;139(4):451-455.
19. Hughes MC, Williams GM, Baker P, Green AC. Sunscreen and prevention of skin aging: a randomized trial.Ann Intern Med.2013;158(11):781-790.doi:10.7326/0003-4819-158-11-201306040-00002.
20. Skin Cancer Foundation website. Recommended products. skincancer.org/products/categories. Accessed May 12, 2016.
21. Edwards EK Jr, Horwitz SN, Frost P. Reduction of the erythema response to ultraviolet light by nonsteroidal antiinflammatory agents. Arch Dermatol Res.1982;272(3-4):263-267.
22. Winkenwerder W, Sawka MN. Disorders due to heat and cold. In: Goldman L, Schafer AI, eds.Cecil Medicine. 24th ed. Philadelphia: Elsevier; 2008:109.
23. Cleveland Clinic. Diseases & Conditions. Avoiding dehydration, proper hydration. Cleveland Clinic website.my.clevelandclinic.org/health/diseases_conditions/hic_avoiding_dehydration. Accessed May 14, 2016.
24. Nadelen, M. Preparing for and playing in the heat. American College of Sports Medicine website. 2012 acsm.org/public-information/articles/2012/01/13/preparing-for-and-playing-in-the-heat. Accessed May 16, 2016.
25. American College of Sports Medicine. Selecting and Effectively Using Sports Drinks, Carbohydrate Gels. 2011. acsm.org/docs/brochures/selecting-and-effectively-using-sports-drinks-carbohydrate-gels-and-energy-bars.pdf. Accessed May 16, 2016.
26. What is a sports drink?mamashealth.com/access/edrink.asp. Accessed May 14, 2016