NYU Langone doctors advise people who have dermatomyositis to avoid exposure to direct sunlight, the most common trigger of skin symptoms. Many people with the condition are photosensitive, meaning they are prone to developing a rash, or experience a worsening of a rash, when exposed to ultraviolet (UV) rays. The reasons UV light triggers dermatomyositis are not well understood, but it may exacerbate the inflammation that leads to a rash and itchiness.
To prevent UV light from affecting your skin, dermatologists recommend staying inside as often as possible during the hours of 10AM and 4PM, when the sun’s rays are strongest. At this time of day, even minutes of exposure may lead to new lesions.
When you are outside, dermatologists recommend wearing clothing that covers as much of your skin as possible, as well as a hat. Also, use a broad-spectrum sunscreen with a sun protection factor (SPF) of 30 or higher. One application is effective for about two hours, so you should reapply it frequently if you are in the sun for more than two hours or go swimming. Be sure to apply sunscreen to the scalp and ears, because dermatomyositis affects those areas.
In addition to applying sunscreen, seek the shade whenever possible. Walk or bike on the shady side of the street and avoid putting your arm out of the window of your car, since it exposes you to UV light.
UV light from tanning beds can also cause a rash. Dermatologists recommend avoiding them altogether.