Purpura fulminans (PF) is a rare and fatal complication of septic shock or diffuse intravascular coagulation (DIC) resulting in skin and soft tissue necrosis. PF can be caused by congenital or acquired protein C (PC) or protein S (PS) deficiency. The most common cause of PF in a neonate is sepsis. In our extremely low birth weight preterm case, due to PF that started in the right-hand fingers, examination was made and protein S deficiency was detected as well as MTHFR (A1298C) and Factor V Leiden (R506Q) homozygous mutations. While being unresponsive to fresh frozen plasma (FFP) and unfractionated heparin (UFH) therapy, we want to highlight the curative treatment with hyperbaric oxygen (HBOT), which has not previously been used in extremely low birth weight preterm infants for this purpose.