erupt

start abruptly; "After 1989, peace broke out in the former East Bloc"

erupt or intensify suddenly; "Unrest erupted in the country"; "Tempers flared at the meeting"; "The crowd irrupted into a burst of patriotism"

start to burn or burst into flames; "Marsh gases ignited suddenly"; "The oily rags combusted spontaneously"

break out; "The tooth erupted and had to be extracted"

become active and spew forth lava and rocks; "Vesuvius erupts once in a while"

force out or release suddenly and often violently something pent up; "break into tears"; "erupt in anger"

appear on the skin; "A rash erupted on her arms after she had touched the exotic plant"

become raw or open; "He broke out in hives"; "My skin breaks out when I eat strawberries"; "Such boils tend to recrudesce"