Pulis felt East should have pointed to the spot for Angel Rangel’s first-half challenge on Chris Brunt and then again when substitute Callum McManaman tumbled in the closing stages.
“The big disappointment is I’ve just watched the video there and it’s two penalties,” Pulis protested after the game.
“The first foul on Chris Brunt is a stonewall banker penalty. Their lad goes for the ball but Chris just touches it away and catches him.
“He (East) is five yards away from it, but there we are.
Albion have now gone five games without a win, their worst run since Pulis was appointed manager almost a year ago, and are now only three points above the Barclays Premier League relegation zone.
They dominated for long periods at the Liberty Stadium but struggled to create clear-cut chances, with Rickie Lambert sending their best opportunity straight at Lukasz Fabianski in the Swansea goal.
“The lads were fantastic, they worked really hard in the second half and upped it,” Pulis said.
“There’s no way we should be losing that game. There is no justice coming away from this game without any points.
Swansea’s victory was their first under caretaker manager Alan Curtis and took them out of the bottom three.
Ki Sung-yueng’s bundled ninth-minute winner came from a free-flowing attack, but Swansea were pushed back and had to scrap.
“We can play better and we have played better in the last couple of games,” Curtis said.
“But we showed a different side to our game, the boys blocked crosses, blocked shots and worked hard.
“I said before the game that as much as we want to maintain our style, we have to find a way to win as well.”
Curtis said there were a “couple of aches and strains” which had to be assessed before today’s trip to Selhurst Park.
Saido Berahino could make his first West Brom start since October at home to Newcastle.
Fabianski, Rangel, Fernandez, Williams, Taylor, Britton (Shelvey 90), Ki, Routledge (Barrow 90), Sigurdsson, Montero (Cork 46), Ayew.
Myhill, Dawson, McAuley, Olsson (Berahino 60),Brunt, Evans,Gardner (Sessegnon 59), Fletcher, Yacob (McManaman 81), Morrison, Lambert.
Roger East (Wiltshire).