Ren Z, et al. - Authors estimated 68,476,920 persons in the USA to study the impact of ultraviolet exposure, climate factors and pollutants on exacerbation of pemphigus following hospitalization. They noticed higher incidences of admission for pemphigus during the summer and autumn months ie, from June to November, with the highest admission rates in the month of July and October. They found an association of hospitalization for a primary diagnosis of pemphigus with significantly lower humidity and higher temperature, ultraviolet (UV) index, particulate matter of ≤ 2.5 or ≤ 10 μm (PM2.5 and PM10).