US National Library of Medicine National Institutes of Health
It has long been known that ultraviolet radiation (UVR), particularly UVB (290–320 nm) and UVA2 (320–340 nm), can induce or exacerbate skin disease in a number of conditions, including systemic lupus erythematosus, xeroderma pigmentosum (XP) and skin cancer (1–5). The most significant source of UVR is the sun, and for years physicians have warned these patients to avoid direct sun exposure. It is now common practice for photosensitive patients to avoid being outdoors at peak sunlight hours and to wear sunscreen and sun-protective clothing for added protection.
Despite these efforts, patients may still be exposed to unwanted UVR from unexpected sources. In 1990, Diffey detailed the most common sources of UVR, listing sunlight and cosmetic tanning units first and fluorescent lamps last (6). It is becoming increasingly clear, however, that the effects of fluorescent lights are more substantial than was once assumed. In 1985, Cole et al. established that commercially available fluorescent lamps emit UVB and UVC (7). These findings proved to be clinically relevant in 1992, when Rihner and McGrath established that lupus patients reported worsening systemic and cutaneous symptoms after exposure to fluorescent light (8). A more recent survey of fluorescent bulbs performed by some of our group confirmed that both fluorescent tubes and energy-saving compact fluorescent light bulbs (CFL) emit appreciable levels of UVA, UVB and even UVC (9). This finding was confirmed by Khazova and O’Hagan, who found that several uncovered CFLs exceeded the UV exposure limits defined by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (10). However, they concluded that enveloped bulbs were safe (11).