Ki Sung-yueng's goal-bound effort in the 62nd minute appeared to hit the hand of Hammers defender James Collins but the home side were not handed a spot kick from 12 yards which interim boss Alan Curtis felt they were entitled to.
"I was not sure at the time, but when I see it again it looks like a penalty," Curtis said.
"Down the bottom you do not get the decisions you deserve.
"We just need that good fortune and we are frustrated.
"In terms of possession we were excellent, we looked like Swansea City again.
"We bossed the game but we just lacked that killer edge up front."
The draw saw Swansea fall into the bottom three having failed to win in their past seven matches.