It has been suggested that all cases of cancrum oris develop from pre-existing NUG, but this is not confirmed. Furthermore, the vast majority of cases of NUG and NUP will not progress to the more severe forms, even without treatment. References
J Lindhe, NP Lang, T Karring (editors) (2008) "Clinical periodontology and implant dentistry" 5th edition, Blackwell Munksgaard, pp. 413,459 
MG Newman, HH. Takei, PR Klokkevold, FA Carranza (editors) (2012) "Carranzas clinical periodontology" 11th edition, Elsevier/Saunders, p. 165
Leukorrhea or (leucorrhoea British English), also known as fluor albus, is a thick, whitish, yellowish or greenish vaginal discharge. It has also been referred to as "the whites". There are many causes of leukorrhea, the usual one being estrogen imbalance. The amount of discharge may increase due to vaginal infection, and it may disappear and reappear from time to time. This discharge can keep occurring for years, in which case it becomes more yellow and strong-smelling. It is usually a non-pathological symptom secondary to inflammatory conditions of the vagina or cervix.Leukorrhea can be confirmed by finding >10 WBC per high-power field under a microscope when examining vaginal fluid.Vaginal discharge is normal, and causes of change in discharge include infection, malignancy, and hormonal changes. It sometimes occurs before an adolescent female has her first period, and is considered a sign of puberty. Etymology
The word leukorrhea comes from Greek λευκός (leukós, “white”) + ῥοία (rhoía, “flow, flux”). In Latin leukorrhea is fluor albus (fluor, "flow" & albus, "white"). Types
Physiologic leukorrhea
It is not a major issue but is to be resolved as soon as possible. It can be a natural defense mechanism that the vagina uses to maintain its chemical balance, as well as to preserve the flexibility of the vaginal tissue. The term "physiologic leukorrhea" is used to refer to leukorrhea due to estrogen stimulation.Leukorrhea may occur normally during pregnancy. This is caused by increased bloodflow to the vagina due to increased estrogen.