[1][2] It is considered that the greatest risk for death is from developing necrotizing enterocolitis (NEC), peritonitis, bacteremia or Clostridium and Escherichia coli sepsis and septic shock, and pneumonia.

[15] According to Garg et al. (2020), new "findings challenge the currently prevailing model that SCN results from mutant ELANE, which triggers endoplasmic reticulum stress, UPR, and apoptosis".

[17] According to Donadieu et al. (2011), the "cyclic aspect ... suggests the existence of a cryptic biological clock that regulates granulopoiesis.

[19] A 2020 study published in Annals of the New York Academy of Sciences about the pathomechanism of CyN revealed that "some HSPCs escape the UPR‐induced endoplasmic reticulum (ER) stress and proliferate in response to granulocyte colony‐stimulating factor (G‐CSF) to a certain threshold at which UPR again affects the majority of HSPCs.

[20] During the condition, which lasts for three to six days and tends to occur approximately every three weeks (but can range from 14 to 36 days),[2][3] the absolute neutrophil count (ANC) is less than 200-500 cells/μL (<0.2-0.5x109/L), with increase of monocyte counts, and mild oscillations of other cells, including a mild anemia.

The treatment following the symptoms should be immediate to prevent infections, especially during a fever when it requires broad-spectrum antibiotic therapy (see febrile neutropenia).

The most important and often life-saving treatment is the preventive therapy of granulocyte colony-stimulating factor (G-CSF), in the form of filgrastim, which regulates the production of neutrophils within the bone marrow, but shortens the neutropenic cycle to about 7-14 days and the duration of the severe condition.

[1][17] The subcutaneous injections, with median dosage of 1.5 μg/kg/day,[18] can be given daily, intermittently once every three days, or timed to just treat the neutropenic period.

Another alternative is hematopoietic stem cell transplantation (HSCT), but is usually practiced in SCN,[1] and in one case between two sibling donors, one of which was undergoing HSCT treatment for acute myeloid leukemia (AML) while the second had CyN and whose marrow was transferred, was also transferred CyN through allogeneic marrow grafting.