You can get CIRS from chronic sinus infections with MARCONS, tick-borne illnesses, ciguatera-contaminated fish, and brown recluse spider bite infections. CIRS is basically your immune system’s dysfunctional response to a biotoxin. The complex test markers, and the variations in how symptoms manifest, make the diagnosis of CIRS difficult. With the improved diagnostics, we also need a group of CIRS indicators and better treatment responses for its proper diagnosis.