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Itching for Some Sun

SunIt may have taken awhile, but now that the sun is out and temperatures are rising, it’s time for the annual reminders about sun safety. Usually these consist of the old adages: wear a broad-brimmed hat and sunglasses, sit in the shade whenever possible, wear protective, tightly-woven clothing, and of course, as Baz Lurhmann famously advised, always wear sunscreen.

But while most people are hoping to avoid painful sunburns or increased risks of skin cancer caused by prolonged exposure to the sun’s ultraviolet (UV) rays, for some, the sun causes a rash of other concerns. Though commonly thought of as a “sun allergy,” rash-like symptoms that result from exposure to the sun may actually be a symptom of what dermatologists call “photodermatoses” or “photosensitive reactions,” broad terms used to refer to a number of conditions that result from a skin sensitivity to the sun’s rays.

So, what is a photosensitivity reaction? And how do people know if they have it? It’s not what some may be thinking: sneezing after looking at a bright light. In fact, symptoms of photosensitivity reactions can actually be quite extreme.

According to Thuzar Shin, MD, PhD, an assistant professor of Dermatology at the Perelman School of Medicine at the University of Pennsylvania, depending on the type and severity of the condition, in addition to a skin rash, patients may experience blistering of the skin or raised spots on areas directly exposed to the sun, itching and burning, fever, fatigue, or joint pain. In extreme cases, she said, symptoms can even be triggered by alternate light sources that emit UV rays, including fluorescent lights.

Though there is a wide range of disorders caused or exacerbated by UV rays, conditions are generally categorized by their catalyst. For example, some photosensitivity disorders occur when chemicals or drugs are ingested or applied to the skin, while others may result from immune disorders. Specific symptoms and severity can help dermatologists determine which type of photosensitivity a patient has, but some of the most common include:

Polymorphous Light Eruption (PMLE): Affecting about 10 to 20 percent of people in the Unites States, PMLE is the most common form of photosensitivity. Like sunburns, PMLE affects people of all skin types, though is much more common in women between the ages of 20 and 40. Symptoms of PMLE usually start in the spring, when the skin is first exposed to the sun after being protected under layers of clothing throughout the winter. In many people with PMLE, symptoms will subside as spring turns to summer and the skin adjusts to continued exposure.

Lime Disease: Not to be confused with Lyme Disease, Lime Disease (also known as phytophotodermatitis) occurs when oils contained in some plants or perfumes applied to the skin are exposed to UVA light. In spring and summer, lemons, limes, parsley and dill are common causes of blisters appearing where skin came into contact with the fruits or vegetables and was later exposed to the sun for an extended period of time. Shin says a rash in a linear or streaky pattern may be a diagnostic clue.

Drug-induced photosensitivity: Many commonly prescribed topical or oral medications are prone to causing dry, bumpy or blistering rashes on sun-exposed skin. Similar to phytophotodermatitis, symptoms result from the interaction between UV rays and certain chemicals in the medications. Non-steroidal anti-inflammatory drugs (which are commonly referred to as NSAIDs and include medications like Ibuprophen and Naproxen), Retin-A, and certain diuretics and antibiotics, are known to lead to either phototoxic reactions that resemble a sunburn, or photoallergic reactions which cause rash-like symptoms.

Lupus: Though relatively rare by comparison, photosensitivity can be caused by other underlying skin conditions such as lupus, a chronic inflammatory disease that occurs when your body's immune system attacks your own tissues and organs. In 2013, Victoria Werth, MD, a professor of Dermatology at the Perelman School of Medicine at the University of Pennsylvania, published a study showing that 83 percent of lupus patients reported having some form of photosensitivity, and overall, 69 percent reported that their condition was exacerbated with exposure to sunlight.

To prevent symptoms caused by sun exposure, covering the skin and eyes and wearing broad-spectrum sunscreen that blocks both UV-A and UV-B rays with at least an SPF of 30 are still the first line of defense. However, when symptoms present or persist, there are a few things that can be done to quell the itches, burns and bumps.

“Cold compresses applied to affected areas tend to work very well for mild symptoms resulting from sun exposure,” Shin explained, adding that over-the-counter creams like cortisone or an oral antihistamine may also be effective. “For more severe or persistent symptoms, patients should seek medical advice from a dermatologist. Once we’re able to identify the cause of the reaction, treatment plans including prescription-strength topical steroids, oral medications or phototherapy would be recommended based on the severity of symptoms and patient’s medical history.”

Though some of these photosensitive conditions are preventable and easily treated, for some, it’s an annual and unavoidable frustration. Shin said that by taking preventive measures and visiting a dermatologist annually, symptoms can be managed so people can spend more time enjoying the summer sun!

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Views expressed are those of the author or other attributed individual and do not necessarily represent the official opinion of the related Department(s), University of Pennsylvania Health System (Penn Medicine), or the University of Pennsylvania, unless explicitly stated with the authority to do so.

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