Present state of Japanese cedar pollinosis: the national affliction

Seasonal allergic rhinitis (SAR) caused by Japanese cedar pollen (JCP; ie, sugi-pollinosis) is the most common disease in Japan and has been considered a national affliction. More than one third of all Japanese persons have sugi-pollinosis, and this number has significantly increased in the last 2 decades. In our opinion the reason why sugi-pollinosis became a common disease in the last half century is the increased number of cedar pollens, with global climate change and forest growth caused by the tree-planting program of the Japanese government after World War II playing substantial roles; dust storms containing small particulate matter from China might also contribute to the increased incidence of sugi-pollinosis. To help minimize their symptoms, many Japanese wear facemasks and eyeglasses at all times between February and April to prevent exposure to JCP and aerosol pollutants. Forecasts for JCP levels typically follow the weather forecast in mass media broadcasts, and real-time information regarding JCP levels is also available on the Internet. Because a large amount of JCP is produced over several months, it can induce severe symptoms. Japanese guidelines for allergic rhinitis recommend prophylactic treatment with antihistamines or antileukotrienes before the start of JCP dispersion. Additionally, sublingual immunotherapy will be supported by health insurance in the summer of 2014. However, many patients with sugi-pollinosis do not find satisfactory symptom relief with currently available therapies. Collaboration between scientists and pharmaceutical companies to produce new therapeutics for the control of sugi-pollinosis symptoms is necessary.