However when a Candida infection becomes systemic this means it has broken through the defensive barrier of the body at some point and has traveled through it, usually by way of the blood, to set up infections in organs or joints. Systemic Candida can, and usually is, very serious. This is more so because often, as clinicians are aware, the disease takes advantage of the weakened condition of a patientâs immune system when they are already suffering from an existing disease.