All big establishments should have a good drainage system.
Living beings are no lesser but frankly a heavy duty society with unbelievable dimensions. We health workers reduce him to a low level pin worm I swear due to total ignorance. Human body has got three major surfaces.
1) Outer or skin (Scalp, skin, sole of palm and foot and nails).
2) Inner surface ( Epithelial layer of Gastro intestinal tract, respiratory tract (nose- lungs -alveoli), Ear, Urinary tract, Genital tract).
3) Cardio vascular system. These inner surfaces are mend to do the classical duties that we all obviously know but draining unwanted and dangerous chemicals from the body after various emergency interventions which probably could be unnatural (a reaction not known to the body but had to attempt to protect body tissues) also is an unsung duty of these drainage systems. As these surfaces are far from sensitive vital organs and nearer to execratory outlets of body usually performs these duties without much noticeable events.
All chemicals, infection and infectious agents vertically entering into body across the cellular barrier should be expelled out across these membranes forcefully through active reactions or sacrifices of minor tissues.
Apthus ulcers ( Mouth ulcers) are such common effect which we always encounter in many infections. This shows how sensitive our buccal mucosal cells and GIT mucosa are. Now in case of Measles towards the end of infection when the measles viruses are carried away from vital organs all the internal surfaces with much more vascularity probably gets pressure to breakopen to expel these viruses. But all these surfaces are very closely associated with various vital operations of our body. Such a heavy inflammatory reaction(Think of the fever and extend of measles rash on the skin and compare it with the possible casualty in case it precipitates on the internal surface) in any name can only be afforded by human body bidding its life. It can cause nephritis, conjunctivitis to blindness, urinary infection, gastritis to gastric ulcers and erosions of GIT, Liver obstruction and inflammation an oncourse brain damage of various grades.
But Koplik’s spot marks the change or timely intervention of our automated immune system seasoned through centuries and generations showcasing not only precision but also aftmost intelligence in redirecting all the reaction which definitely is going to kill the body to the most safest and largest organ of the body which is mend to conceive( If not it would have been placed inside the skull and rather than outside the body) all the hardships of universe to protect our body the skin.