Probably the single most important and comprehensive area of prevention education currently concerns UVR.

"Consumers in developed countries should remain vigilant and not purchase anything operating or produced with ozone-depleting substances when good alternatives are available."76

Prevention

In the case of environmental dermatoses, once a diagnosis is certain and treatment rendered, personal protection, avoidance and hygiene are strategies to reduce the risk of such afflictions in the future, especially if they represent the immune-mediated types of conditions. Patient education and awareness is another important strategy to prevention.

UV Exposure

Probably the single most important and comprehensive area of prevention education currently concerns UVR. Because of the well-recognized role of UV exposure in the pathogenesis of skin cancers and the long latency period, it is important to stress preventive measures as early as possible to parents of young patients.65,66  There is a great wealth of information on preventing skin cancers.

Avoidance of exposure is the most important means of prevention. Peak exposure time for UV rays is between 10 a.m. and 3 p.m., so one approach is to minimize outdoor activities during this time.67 One figure cites that the UVR level is ten times greater at noon than it is at times three hours earlier or later than noon.68  A useful rule advises that “if your shadow is shorter than you, the risk of sunburn is substantial.”69  

UV radiation varies seasonally in the northern hemisphere with the highest exposure in June and July in Canada. The UV index is a summary calculation that incorporates several factors to estimate the intensity of UV light and the consequent time to produce a sunburn in those who are of skin type II.  Environment Canada provides forecasts of the daily ultraviolet (UV) indices for select Canadian cities. During summer months, most media will report daily values for the UV index. Parents and caregivers of young children should be aware of such reports of the UV index.

Other practices that may reduce exposure are the use of appropriate clothing and sunscreen (sun protection factor of at least 15). Wide-brimmed hats and clothing made of relatively opaque material provide significant protection from UVR exposure. It is clear that our knowledge of the efficacy of sunscreens is still evolving. Sunscreens are designed to absorb UV radiation and to prevent erythema. Early studies state that use of suncreen in childhood will significantly reduce the chances of developing NMSC.70

A recent review suggests, however, that there is some question as to whether sunscreens prevent cell photodamage and molecular changes that appear to result from suberythemal doses of UVR, or protect from exposure to UVA radiation. Recent experimental research has also demonstrated that several of the most common chemicals found in sunscreens display estrogenic activity.71 There remain, therefore, some questions surrounding the true efficacy of sunscreens in preventing skin malignancies.72

There is also controversy over whether it is appropriate to apply sunscreen to infants under six months of age because of the immaturity of both the infant’s skin and metabolic capacities.73 As a rule, it is best to ensure that infants under six months are not directly exposed to the sun because their smaller body size renders them predisposed to overheating. Infants should also have adequate protection with clothing or screens that will block UVR.

The above precautions also hold for preventing excess exposure of children in the day-care and school settings. Parents should be explicit in expressing to caregivers, teachers and their older children how best to protect their child from exposure to UV rays. There are a number of resources that can assist them in this vein. We must also not overlook the fact that teens, who are more autonomous, may have even greater opportunity for excess exposure to UVR through work and recreational activities.

Data on fair-skinned individuals living in Northern Europe indicate that the risk at age 70 of NMSC in someone who worked indoors and did not sunbathe is about 2 to 3%. Not surprisingly, an outdoor worker who did not sunbathe has a threefold higher risk (7.4 to 11.1%) of NMSC. However, even someone who worked indoors but sunbathed for about two weeks of the year has a comparable and even slightly higher risk of developing NMSC as the non-sunbathing outdoor worker.

Primary Prevention

Because of predictions that reductions in the atmospheric ozone layer are likely to lead to much higher average exposure in current and future generations, enhancing the public’s awareness of primary prevention strategies is now even more important. The 1987 Montreal Protocol on Substances that Deplete the Ozone Layer was an international agreement that has called for a total elimination of ozone-depleting substances by 2005.

Developed nations have made efficient strides toward reducing consumption and emissions of such substances, undoubtedly averting many millions of cases of skin cancer and eye cataracts. However, there is still concern as to how effectively this phasing out can be accomplished in some developing nations.75

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