If you get a red, itchy rash after being in the sun—especially in the spring or early summer each year—chances are you have sun (or photo) sensitivity. This reaction, sometimes called “sun poisoning” or “sun allergy,” is different from a sunburn. In most cases the rash occurs several hours after sun exposure and can last for a few days; more rarely, hives appear within minutes of sun exposure and subside more quickly. Sun sensitivity can be uncomfortable and unsightly, and it can limit outdoor activities and spoil vacations.
Causes of photosensitivity
It’s not clear why people develop sun sensitivity, but the immune system is thought to be involved, and the condition may run in families. People with lupus (an auto-immune disease) and porphyria (a rare inherited metabolic disease) are more susceptible. Having rosacea or other skin conditions can increase your risk. Some medications—including tetracycline and other antibiotics, some older antidepressants, and certain drugs takenfor hypertension, high blood sugar, heart conditions, and acne—also increase sun sensitivity, as can some herbs, such as saw palmetto and St. John’s wort. Or it may be triggered by something you put on your skin, such as a fragrance, cosmetics, or a lotion. Ironically, sunscreens are sometimes the culprit.
How to treat photosensitivity
The rash usually goes away on its own, and many people become less sensitive to the sun with gradual, increased exposure. You may find some relief with over-the-counter anti-inflammatory/anti-itch creams. But if your symptoms are severe or worsen from year to year, your doctor can help pinpoint potential causes and prescribe topical or oral medications. A photo-patch test can reveal whether a skin product is to blame. Light therapy may be used to desensitize skin to the sun.
If you are sun-sensitive, you should take extra steps to protect yourself when outside. Limit time in the sun, and wear protective clothing and a wide-brimmed hat. A broad-spectrum sunscreen is a must—but if you find that you are sensitive to one product, or if it doesn’t prevent symptoms, try another one with different ingredients. Sunscreens that contain only zinc oxide or titanium dioxide, which act as physical sun blocks, may be better tolerated than ones that contain chemical UV-absorbing ingredients, such as cinnamates.
Be especially careful of sun exposure early in the summer or if you travel to a sunnier climate or higher altitude than where you live.
Can dietary supplements help?
Some studies suggest that consuming carotenoid-rich fruits and vegetables confers some degree of photo-protection. But despite claims that beta carotene supplements reduce photosensitivity, there’s not enough evidence to support the use of high doses of this—or any other—carotenoid, except in the case of a rare genetic condition. Moreover, there are safety concerns about high-dose beta carotene supplements.