The Facial Triangle of Danger (Even Death)

Image by SpooSpa from Wikipedia

If you draw a line between the eyebrow to the corners of the lip, a triangle is created which delimits a region esoterically known as the "danger triangle".

Why is this region considered dangerous?

It's because infections within this region can lead to infections of the brain (rarely). Why? The blood supply within this triangular area communicates with the cavernous sinus found at the bottom of the brain. This anatomic structure is a major source of venous drainage of the brain.

If the cavernous sinus gets inflamed/infected due to a rip-roaring pimple of the upper lip, it could lead to multiple facial abnormalities due to injury of the numerous cranial nerves that go through it including:

• Inability to move the eyeballs (CN3, 4, 6)
• Numbness, pain of the skin over the forehead and cheeks (CNV1, V2)
• Loss of pupillary constriction (CN3)
• Visual loss/changes (CN1)

The cavernous sinus could also become thrombosed.

Cavernous Sinus shown by red arrow. Taken from Sonoworld.

From there, the infection can spread to the rest of the brain and potentially can even lead to death if not treated promptly and aggressively.

Of course, tiny infections like a small pimple or a small laceration due to biting a lip is not going to cause problems.

However, rapidly progressive major infections of the skin with abscess formation do need to be treated cautiously.  Typically, such patients are hospitalized on IV antibiotics until definite and significant improvement can be seen at which time patients can be discharged home on oral antibiotics.

At which point a "minor" infection becomes "major" requiring hospitalization is a judgement call.

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Cold Sores Due to a Single Gene

Specifically, individuals who suffer from cold sores triggered by Herpes Virus Simplex - 1 (HSV-1) several times a year may have a single nucleotide polymorphism in their gene C21orf91 – dubbed rs1062202. Researchers have suggested it be called by the more "easy-to-remember" name Cold Sore Susceptibility Gene 1 (CSSG1).

Having this genetic change of swapping a thymine to a cytosine nucleotide was significantly associated (p=0.0047) with more frequent cold sores. Analysis has also found collections of 5 variants that are transmitted together with the C21orf91 gene of which two seemed to be neutral in terms of cold sore frequency, one was protective, and two were associated with increased susceptibility.

What does this all mean for an individual? It means if your parents get them a lot, than you may too.

Such individuals may benefit from regular use of anti-viral antibiotics to prevent such frequent recurrences.

Reference:
C21orf91 genotypes correlate with herpes simplex labialis (cold sore) frequency: Description of a cold sore susceptibility gene. J Inf Dis 2011; DOI: 10.1093/infdis/jir633.

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