It’s officially Derby week in Louisville, which means the sun shines bright on our Kentucky home. Big hats and fascinators will crowd Churchill Downs as spectators gather to watch the 148^th running of the Kentucky Derby. Regardless of your outfit choice, the School of Medicine wants to remind you that your Derby hat is more than a fashion statement: it’s a chance to protect yourself from the sun’s harmful rays. Jeffrey Callen, M.D., and chief of our division of Dermatology weighed in with his suggestions for sun protection this Derby season.

Q. In terms of sun protection, what is the general rule of thumb in terms of exposure and sunscreen application?

A. Sunscreens are imperfect in their protective effects for several reasons. First, is that as their name suggests they are a screen. Think of a screen door, depending on the weave of the metal used to make the door, a person might see through the door relatively unimpeded or if the weave is really tight, it might be impossible to see much. Sunscreens are tested and given a number indicating their Sun Protective Factor (SPF), the higher the number, the higher the protection. However, an SPF 60 does not represent double the protection of an SPF 30 sunscreen. The second issue is adequacy of application which in many clinical settings is inadequate and thus the sunscreen might not function as its SPF suggests. Thirdly, the SPF only measures the effect of Ultraviolet B (UVB) light and Ultraviolet A (UVA) is not measured by this designation. Although in general UVA does not cause sunburn, it enhances the effects of UVB. The fourth issue is the length of time that an individual is exposed to UV light. During day-long events like the Derby it becomes necessary for reapplication of sunscreen to have continued benefit, and this is less frequently applied in the necessary amount than the first application.

Bottom line - don't depend on sunscreens as a sole method of protection. Use good sense in avoiding direct exposure by staying in shaded areas, as well as wearing clothing that protects against the sun including hats with a wide brim.

Q. What is the best sunscreen I can purchase from a drug store?

A. There is no single "best" sunscreen. Look for products that are labeled with an SPF of 30 or more, are broad spectrum and are water resistant.

Q. Scenario: It’s too late. I didn’t apply sunscreen in time, and I’ve burned myself. Now what?

A. Burns from sun come in degrees. For mild redness, only symptomatic treatment is needed including cool compresses, topical emollients, and an oral nonsteroidal anti-inflammatory drug (e.g., naproxen or ibuprofen). If the sunburn is severe, which would be indicated by blistering and systemic symptoms, (e.g., fever, nausea, vomiting, etc.) you might need to be hospitalized.

Severe blistering sunburns have been linked to an increased risk of melanoma. If you have had such a burn, you should see a physician (preferably a dermatologist) with some regularity (depends on your skin type, how many burns you have had and your age among other factors). 

Q. Any other sun safety tips?

A. Limit your exposure to direct or reflected sunlight. You can get adequate levels of Vitamin D through diet and supplements.

He leaves us with this last statement of wisdom: “An ounce of prevention is worth a pound of treatment.” Bet wisely on your health this Derby weekend and best of luck at the races!