10 truths about UV radiation

Lupus Foundation of America

Resource Content

  • People of ALL skin colors are at risk for skin damage and many other harmful effects of ultraviolet (UV) radiation from the sun, and for some people, from indoor fluorescent or halogen lighting.
  • In people with lupus, UV exposure can trigger not only worsening of skin lupus and other types of photosensitivity, but activation and worsening of systemic symptoms—including joint pain and kidney disease.
  • UV radiation is classified by wavelength—the distance between the peaks in a series of waves of light. UVA is the longest wavelength. It penetrates deep into the middle layer of the skin and can cause long-term damage. UVA a danger every day, regardless of weather, location, or altitude (even passing through window glass). UVB is a shorter wavelength that reaches the outer layer of the skin. UVB varies in intensity depending on the weather and season. It’s stronger in summer and more intense at midday, at high altitudes, and near the equator.
10-2 Daytime hours when UV rays are most intense.
  • The hours between 10am and 2pm are when the sun’s UVB rays are most intense. Whenever possible, plan outdoor activities in the early morning and in late afternoon (and try to always wear sun-protective clothing and apply broad-spectrum sunscreen no matter what time of day it is).
  • UV radiation is more intense when reflected by water, sand, and snow, in locations closer to the sun (such as mountains), and in countries near or at the Equator. 
  • Cloud cover and shade do not provide complete protection from UVA. 
  • Medications may increase the body’s sensitivity to the sun—talk to your pharmacist or doctor about your increased risk of photosensitivity especially if you’re taking antibiotics, anti-inflammatory or blood pressure medications, or methotrexate (among many others).
  • If limiting your UV exposure prevents your body from making enough vitamin D, eating foods with vitamin D and taking vitamin supplements can help you meet your daily requirement. Talk to your doctor about what your vitamin D level is (you may need a blood test to find out) and what it should be. 
  • Fluorescent and halogen light bulbs emit UVA radiation that can cause flares of lupus in people who are especially photosensitive. Plastic blocks both UVB and UVA, and plastic light shields are available for many types of indoor bulbs—you may want to request them as a necessary accommodation at your workplace.
  • Tanning is not “healthy”—it’s the body’s response to skin cell damage. Tanning beds are especially dangerous for anyone who is photosensitive, as the light wavelength used is primarily UVA, which penetrate deeply into the skin.