Lee Trundle struck home from the spot to put the Swans 2-1 ahead, and left United with a mountain to climb.
Laws said: "I will view the video of the incident and then decide what to do, but my first thoughts are that it was the wrong decision.
"It changed the game completely as you cannot play at Swansea with only ten men.
"I am pretty sure we will put in an appeal, but while we may rescind the red card, we cannot wipe out the goal scored as a result of it.
"Despite the defeat we have been playing well and promotion is still very much in our own hands, and while it is a dent to our promotion push, there is still a long way to go."
Swansea made their one man advantage count, pushing Scunthorpe back int he final half hour and had a Kevin McLeod effort ruled out for offside.
Boss Kenny Jackett said: "We deserved to win because we played well.
"I picked the right team for this particular game and it was justified by the way we played.
"The opening goal was well worked and it was definitely a penalty, but it was disappointing to concede an equaliser from a set piece and they never created a great deal throughout the match."
The win sees the Swans move level on points with United, who stay second ahead of three other teams thanks to superior goal difference.