Parenteau scored his second straight game-winning goal in helping the Islanders continue their recovery from a miserable start to the season.
New York won just five of its first 28 games, but has captured six out of eight since then.
The Islanders had a 3-1 lead with time ticking down in the second period but Valtteri Filppula scored for Detroit with 9 seconds left in the stanza and Tomas Tatar produced a goal in his NHL debut midway through the third to tie it.
Tatar was called up Friday from Grand Rapids of the American Hockey League.
Parenteau scored in the fourth round of the shootout Wednesday for a 2-1 victory over Pittsburgh.
Dwayne Roloson made 38 saves to get the win. Howard gave up four goals on 23 shots.