The Shrimpers saw goalscorer Freddy Eastwood given a straight red card by referee Paul Melin for violent conduct after 52 minutes.
Striker Eastwood, who had put the hosts ahead after 14 minutes, tangled with Andy Holdsworth as he made a forward foray, got up and pushed the Huddersfield defender.
Southend started well and a Mark Gower cross was headed goalwards by Wayne Gray but Terriers keeper Paul Rachubka spectacularly turned the ball onto his cross bar, only for the loose ball to fall to Eastwood, who stabbed home from six yards.
Huddersfield saw Gary Taylor-Fletcher and Pawel Abbott both fire wide before they finally forced an equaliser in first half injury time.
Rachubka's upfield kick found Abbott, who beat Blues left-back Che Wilson and fired beyond a diving Darryl Flahavan for his fourth goal of the season.
The Terriers dominated going forward following Eastwood's dismissal but failed to make the most of the chances they created.
Flahavan denied Holdsworth and Abbott, while Hudson and Taylor-Fletcher were unable to get their attempts on target.
But it was Abbott who denied Martin McIntosh a winner when Danny Schofield's right-wing corner was headed goalwards by McIntosh, only for the ball to hit Abbott and roll to safety with 67 minutes gone.
McIntosh forced another save out of Flahavan after 79 minutes and Hudson dinked inches wide from 16 yards a minute from time.
Southend never really threatened a goal as lone striker Wayne Gray found himself without much support up front.
And even the introduction of 250-goal forward Shaun Goater for his home debut was insufficient for him to get his second goal of the season.