CSS is characterized by three stages. The prodromal phase consists predominantly of asthma, rhinosinusitis, and nasal polyposis, followed by a second phase, which is characterized by peripheral blood and tissue eosinophilia, and then develops into the advanced vasculitic phase. Asthma is considered a unifying feature, reported in up to 96% of cases. From the onset of asthma, there is a latency period to the vasculitic phase, which is reported as 3 to 9 years, on average. Around the time of CSS onset, patients commonly experience constitutional symptoms of malaise, diffuse myalgia, and polyarthralgia. During the eosinophilic and vascular phases, the disorder involves multiple systems, including neurologic, cardiovascular, renal, gastrointestinal, and skin manifestations of the disease.