ENJOYING THE SUMMER WITH LUPUS ERYTHEMATOSUS Anthony P. Fernandez, MD, PhD
The onset of summer often triggers mixed emotions in patients with lupus erythematosus (LE). On the one hand, there is a desire to enjoy beautiful weather and participate in outdoor activities with family and friends. On the other hand, concern that sun exposure will trigger disease flares and/or new LE manifestations can cause significant anxiety. An understanding of how sunlight (ultraviolet radiation, or UVR) can precipitate or aggravate LE, in addition to strategies to mitigate risk of excess UVR exposure, can optimize the enjoyment of summer months for LE patients. Photosensitivity represents a hallmark symptom of LE and often manifests as cutaneous lupus erythematosus (CLE), which may occur as the sole manifestation of LE or as one manifestation of systemic LE (SLE). In fact, the skin represents the second most common
organ involved in SLE1. Photosensitivity can also lead to symptoms of fatigue, joint pain, or even onset of lupus nephritis in SLE patients exposed to excess UVR2,3. Importantly, there has been significant progress in understanding how excess sun exposure contributes to the onset/aggravation of LE. It is thought that the accumulation of apoptotic (dying) cells is fundamental to the pathogenesis of both SLE and CLE4. Research suggests that, in a background of LE immune system dysfunction, sun/UVR exposure leads to pathologic accumulation of apoptotic cells in the skin5. Under normal conditions, immune system cells efficiently clear apoptotic cells. However, LE patients demonstrate impaired or delayed clearance of apoptotic cells in the skin, leading to the accumulation of UVR-induced cellular debris. This debris includes intracellular,
DNA-containing nuclear material that promotes the formation of LE autoantibodies and activates cells to secrete interferon (IFN)-α, a key molecule involved in LE inflammation6. Excess sun/UVR exposure also triggers production of other pro-inflammatory molecules known to be involved in LE inflammation and onset of various LE symptoms and physical manifestations7. With this in mind, it is important for patients with LE to balance enjoyment of the outdoors during summer months with adequate sun/UVR protection. Several important points are critical to understand in order to accomplish this balance. First, it is important to recognize that the threshold sun/UVR dose needed to trigger LE flares is lower than that of a sunburn8. So recognizing the amount of sun exposure one can personally tolerate without LIVING WITH LUPUS MAGAZINE
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