It was a beautiful sunny midsummer afternoon, perfect for feeding the ducks. My seven year-old niece Crystal was staying with me, and after finishing our lunch of grilled cheese sandwiches and tomato soup, I loaded my backpack with water and a bag of old bread scraps before setting out for the duck pond at a local park.
Crystal tossed the first bread bits as far as she could. Soon the ducks swam over to gobble up the floating treats, creating squawking competition for each bit of bread. Laughing, she continued pitching the rest of the bread piece by piece into the quacking crowd. Once the bread was gone we headed for the swings, pumping our legs to carry us higher and higher into the cloudless sky.
“Aunt Louise, I feel hot. ”
“Let’s head for that big tree over there, and I’ll get you some water.”
Opening my pack, I fished out a water bottle and turned around to offer it to Crystal, nearly dropping it in shock when I saw her flaming red cheeks and arms. Heading back home, I kept thinking, “She had sunscreen on, so how could she have burned so quickly?”
Once we got home, I zipped into the kitchen to get a damp towel for Crystal’s face. Sitting right next to the sink was her prescription bottle of antibiotic. I’d given Crystal her morning dose right after breakfast and then left it out on the counter to remind me to give her next dose at dinner. Could her medicine have caused her to burn even through her sunscreen?
When my brother had dropped Crystal off the day before I had focused on the dosing instructions printed on the label of her bottle but overlooked the small yellow sticker over on the side that warned about exposure to sunlight. Luckily, her “burn” faded by dinnertime, but I’ve never forgotten how scared I felt.
Exposing our skin to sunshine causes our skin to react, either by “tanning” or “burning”. Sunlight contains ultraviolet radiation; there are wavelengths called UVA and UVB that can trigger skin reactions like rash, itching and even exaggerated sunburn. These effects are called photosensitivity reactions.
Sunburn, skin cancer and accelerated skin changes such as wrinkles and spots called photo aging are caused mostly from exposure to UVB radiation. UVB rays are most intense between 10 in the morning and 4 pm, and help our skin produce Vitamin D. UVA radiation triggers photosensitivity reactions in people taking certain medicines, like Crystal. Normal sunlight has approximately 20 times as much UVA radiation as UVB. Because UVB radiation causes more sunburn, 96% of the rays from tanning beds are UVA wavelengths.
Crystal’s antibiotic increased the sensitivity of her skin to the UVA wavelengths in the sunshine we played in that July afternoon. Back then; the sunscreen she wore protected her against UVB rays, which can cause sunburn, but not against UVA wavelengths, which can trigger photosensitivity skin reactions. Today’s sunscreen products are formulated to protect against BOTH UVA and UVB radiation.
The measure of how much protection a sunscreen product gives is called its SPF (Sun Protection Factor). The bigger the SPF number, the better the protection. For example, if you properly apply a sunscreen with an SPF of 15, you could stay out in the sun 15 times as long without burning as you could without it.
Sunscreens come in two main types: chemical and physical. Chemical sunscreens work by absorbing specific wavelengths of UV radiation before they penetrate your skin, while physical sunscreens reflect and scatter UVA and UVB radiation. The lighter your skin, the more quickly it can burn and the more protection you need.
4 Tips for Taking Medicines That Can Cause Sun Sensitivity:
- AVOID tanning beds or going outside into direct sunlight until you finish the medicine. When going outside during the day, cover up with long sleeves and a hat with a brim at least 4 inches wide, or apply sunscreen with UVA and UVB protection.
- Apply sunscreen at least 15 minutes before you expect to be outside in the sun. To be most effective, sunscreens need time to bind to your skin.
- Don’t skimp when applying sunscreen. The FDA estimates an adult in a swimsuit should use about 4 and 1/2 teaspoonfuls when applying sunscreen to their whole body.
- Reapply your sunscreen frequently, especially after swimming, playing in the water or sweating. And don’t forget to reapply sunscreen after drying yourself off with a towel.
