From my research, postule means to claim or propose something is true without providing evidence or proof, as is postulate.  

pustule, however, is a bulging patch of skin full of yellowish fluid called pus. 

Pustule (Middle English) comes from the Latin word pustula. 

Pustules may form when your skin becomes inflamed due to allergic reactions to food or insect bites. 

Distantly related to measles and chicken pox, smallpox has been a terrible scourge throughout humanity's history. Marked by many small, painful pustules, it is a highly infectious disease that has changed the course of entire empires.

The Variola virus is thought by many to have been responsible for the Antoine Plague* which started the long process of Rome's collapse. It decimated the native tribes of North and South America when it was carried to the new world by European explorers, traders and colonists.

Although Smallpox is thought to have been eradicated, the world may not yet be done with the Variola virus. Given its status as a highly contagious disease which has not been mass vaccinated for in over fifty years, its potential as an exceptionally lethal biological weapon cannot be ignored.

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* - in the interest of full disclosure, there is some debate whether it was the Black Plague or Smallpox. Either way, it took the starch out of Rome at the height of her power.

Pustules are a major part of any victim of acne vulgaris. Mine began at age 11 when Mother would get out the bobby pin after dinner and go to work on the blackheads on and around my nose. What she didn't know, of course, was that she was only contributing to the problem. Father threatened to shave my head, as occurred to his younger brother, when the first whitehead appeared. At 74, I still have a pimple show up in the usual places. It's the ingrown hairs that leave the largest scars and tend to return at the most inopportune moments.