The sun causes us problems because many of our symptoms are photosensitive. Photosensitivity is one of the most aggravating triggers of our disease. It doesn't take much exposure to ensure that we have a reaction of pain. Lupus patients are very sensitive to UV rays, especially those who suffer from Discoid Lupus. It is a known trigger for a flare! That is why it is so important to wear sunscreen when outside in the sun. But what most people don't realize is, they should be wearing UV protection inside stores as well.
UV rays from the sun can trigger reactions in the skin in the form of a rash, or purple spots under the skin called pupura, but will also cause muscle and joint pain, fatigue and all around malaise.
Lupus sun sensitivity and UV light sensitivity (photosensitivity) is present in about 90 percent of patients with systemic lupus erythematosus (SLE), 40 to 60 percent of patients with discoid lupus, and about 70 percent of patients with subacute lupus erythematosus.
In systemic lupus, sun exposure can also cause the classic “butterfly” shaped rash that extends across the cheeks and bridge of the nose. In discoid lupus, sun exposure causes coin-shaped (“discoid”) lesions in exposed areas. In subacute lupus, sun exposure causes red, raised, circular lesions on the back, chest and arms, which can be confused with psoriasis. In addition, in lupus, sun exposure may cause other rashes, as well as joint pain and increased fatigue, as I mentioned above.
For us, sun exposure, even for as little as 30 minutes, causes us to develop migraine headaches, makes us feel nauseas and/or we will experience painful joints. Additionally, exposure to the sun can cause our disease to flare-up (an increase in the activity and symptoms of the disease. This may cause an acute attack of arthritis, pleurisy (chest pain when inhaling), fever, kidney disease, and even epilepsy.
Scientists think that ultraviolet light (which is in sunlight, fluorescent lights, photocopiers, and VDUs) create antigens (protein molecules) on the skin surface which react with antibodies. The antibodies cause white blood cells to be drawn to the skin and attack it and a rash appears. The redness and inflammation may also be due to excessive nitric oxide present in the skin after lupus patients are exposed to sun. In lupus, sun is more likely to cause problems than artificial sources of light, but be aware that artifical sources of light can cause us problems also.
The UV rays in sunlight causes damage to the skin (keratinocytes), resulting in sunburn. In normal people, the sunburn goes away because the dead skin cells get cleared away quickly. In lupus, the sun causes the damage to skin cells but the cells are not cleared away very well. The releases of the contents of the cells cause inflammation. In addition, the cell contents, which include Ro, are able to cause an immune response. The immune system responds to the cells by creating autoantibodies which attack the skin.
Prolonged sun exposure by those who work outdoors causes a three-fold increase in chances of developing systemic lupus erythematosus. For people who already have lupus, the sun and UV light can cause or make worse rashes and systemic symptoms (worsening symptoms throughout our body).
In patients with lupus, sun exposure causes us to have antibodies to Ro. In addition, other tissues in the body are affected because autoantibodies travel to other tissues in the body, binding to target molecules and creating immune complexes. The immune complexes cause inflammation and the systemic symptoms of lupus.
In lupus, sun exposure causes rashes in about 60 percent of patients. Other problems are reported by about 10 to 20 percent of patients with lupus after sun exposure. Be aware, however, that sometimes, the effects of sun exposure may not show up for a couple of weeks after exposure (although for some of us, the effects show up immediately).
For Lupus patients, it is recommended that sun exposure should be limited in order to prevent rashes and to prevent our disease from going into an active phase or a worsening phase. You should stay out of the sun as much as possible, wear protective clothing and sunscreens (SPF 25 or greater), and stay out of places where UV exposure is at it’s greatest. It is also wise to be aware that reflected light from snow and water magnifies the exposure to the sun.
I hope that I've answered your question. Please let me know if you need anything further.
Peace and Blessings
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