Slather on the sunscreen and you'll be protected from a blistering burn, right? Not always.The "margarita burn" is well known, but there are other things that can decrease the effectiveness of sunscreen that you may not know about.
It's important because even one blistering sunburn during childhood or adolescence can nearly double the risk of developing melanoma. Five or more sunburns between the ages of 15 and 20 can increase your skin cancer risk by as much as 80 percent, according to the American Academy of Dermatology.
To find free skin cancer screenings by the American Academy of Dermatology go here
1. iPad and iPhone
Most people won't use a reflector to get a tan but the biggest surprise is the risk associated with indirect sunlight reflected from electronic devices. A 2015 study in the Journal of the American Academy of Dermatology showed that an iPad increases the ultraviolet light (UV) exposure by 85 percent and that an iPhone increased the sun's reflection by 35 percent.
There are two types of UV exposure: UVB rays from the sun can cause superficial and immediate skin damage— sunburns — depending on the amount of exposure. UVB rays are thought to cause skin cancer, according to the American Cancer Society. UVA rays penetrate deep into the skin and cause aging and wrinkles.
The real take home message is that you need to wear sun protection regardless of where you are and when you are near any type of reflective surface you need to seek shade in addition to applying your SPF, according to New York dermatologist Dr. Debra Wattenberg.
RELATED: Does a sun umbrella protect against harmful rays?
2. Advil, Aleve and Benadryl
Most people don't realize that over the counter anti-inflammatories like Advil and Aleve or OTC Benadryl can make you more sensitive to the sun. These everyday products can increase your skin's sensitivity and make you think your sunscreen doesn't work.
3. Limes, lemons and celery
Citric fruit when applied directly to the skin can cause a chemical burn when the juice reacts with sunlight on your skin, a condition called phytophotodermatitis.
Celery can cause a burn from direct contact as well as from actually eating a lot of it. These types of reactions can sometimes develop over a few days long after you finished the margarita, so make sure to wash your hands and any exposed skin after a spill.
RELATED: How lime juice can lead to nasty sunburns
4. Perfume with musk, lavender and lemon
Wearing fragrance to the beach is a really bad idea because so many of the ingredients in these products can make your skin more sensitive to the sun and can create a localized burn.
5. Insect repellents and bug sprays
When applied together, insect repellents can decrease the ability of the sunscreen to work increasing the chances of burning. There are studies to show that the combination can decrease the effectiveness of sun protection by almost 30 percent.
That's why it's best to reapply sunscreen every 2 hours, then apply bug spray according to the directions.