LAUSR

advanced cases, the optical field frequently worsens. By correlating basic and epidemiological research studies, we have helped elucidate the physiopathogenesis of AP, which we consider to be a subtype A or B type IV hypersensitivity reaction. In 2014, by TUNEL (transferase-mediated dUTP nick-end labeling) technique on paraffin-embedded tissues that were obtained by biopsy of lesions on the skin and lip, it was found that apoptosis was the last step in the hypersensitivity reaction, raising the possibility that other external factors, besides solar radiation, were triggers. These results were corroborated by immunohistochemistry, wherein apoptosis was activated through the intrinsic apoptotic pathway because of external factors. Two clinical studies complement these results. The first study was published in 2014 and included 44 cases and 88 controls, reporting that there was no relation between AP and socioeconomic variables but that AP was linked to variables of environmental exposure. In the second study, which we published at the end of 2017, we identified the main risk factors that were associated with AP, such as solar exposure, cohabitation with domestic animals or farm animals, and exposure to wood smoke. The results of many studies have allowed clinicians to better understand this condition. In summary, AP is a chronic and inflammatory disease that affects photoexposed areas. It is present in darker-skinned populations with a strong Amerindian component. The diagnosis of AP is established by clinicopathological correlation and can be aided by phototesting and HLA genotyping. The condition is usually manageable under strict photoprotection and sun avoidance; in severe cases, systemic treatment options range from steroids or antimalarials to thalidomide or photohardening via phototherapy; clinical improvement after treatment often improves quality of life of patients.