Sunlight is vital to life on Earth. For humans, sunlight helps regulate our circadian rhythm and metabolic processes, such as vitamin D synthesis. But for some people, exposure to the sun's rays actually trigger severe allergic reactions.
Indeed, for people with a condition known as polymorphic light eruption (PLE), the sun's rays cause a rather uncomfortable, itchy, prickly rash on the skin. Moreover, instead of a healthy bronzed glow, the sun causes the sufferer's skin to turn blotchy and red. So far, there are more questions than answers about this condition. But scientists do know that this immune response affects more women than men, and that the skin on the chest and trunk are most commonly affected. And the condition isn't as rare as you may think - around 10 percent of the population suffer from this sun-related allergy.
Rather than a rash, another type of sun allergy causes hives on skin exposed to the sun. This condition is known as solar urticaria. Sufferers develop itchy hives that can turn into welts. And the welts can lead to life-threatening anaphylactic shock. Fortunately, this condition is much rarer, and can be treated with antihistamines.
Watch the video to learn more weird ways the body can react to the sun's light.