The Blues' dismal home form was again their downfall as Albion picked up their first point in four games as a result of Nathan Ellington's first goal since November 30.
Ellington's strike cancelled out a 49th-minute penalty from Mikael Forssell and came just 90 seconds after he replaced Kevin Campbell.
Birmingham were forced to hang on grimly in the closing stages as they were over-run and only survived because Ellington smashed an injury-time effort against the underside of the bar.
It was hardly surprising in the circumstances that the fear factor dominated the match.
Birmingham displayed more positive attacking ideas in an attempt to break the stalemate but they failed to carve out any clear-cut opportunities in a ding-dong opening 30 minutes.
Ominously for Albion the lack of pace from Kevin Campbell was a handicap and the former Arsenal and Everton striker posed little threat.
Diomansy Kamara was Albion's live-wire but he became increasingly frustrated by his lack of success breaking through another makeshift Birmingham defence.
David Dunn opened brightly for City on only his seventh start of the season, but he too tailed off as the game progressed.
Dunn, now back to full fitness following a back operation, provided the only real attempt on goal when he hit a first-time shot just wide after being set-up by Emile Heskey.
Home skipper Mario Melchiot picked up the first booking of the match when he voiced his opinion to referee Phil Dowd after the official rejected a penalty appeal following a tackle by Curtis Davies on Forssell.
But the major talking point of the first half occurred in the 29th minute when Jonathan Greening outpaced Stan Lazaridis to provide a low cross into the middle.
The onrushing Kamara, with an open goal at his mercy, sliced his shot wide and subsequently disappeared into the crowd to hide his embarrassment.
There was an even worse miss six minutes before the break when Kamara's pass found the unmarked Kevin Campbell, who weakly shot against the post.
From the rebound Jan Kozak watched his shot cleared off the line by Martin Taylor.
Surprisingly the confrontation between Jermaine Pennant and Paul Robinson did not materialise as the little winger struggled to get into his stride, while the Albion full-back limped out of the game just before half-time.
There was some doubt whether Pennant would resume in the second half because of a leg injury, but he continued and four minutes after resuming Birmingham took a somewhat fortunate lead.
Davies was alleged to have fouled Forssell in the area and the Finn duly converted the penalty for only his second Premiership goal of the season.
Birmingham then survived a dangerous spell when Lazaridis headed over his own goal before Maik Taylor produced the save of the game to keep out a long-range rising drive from Junichi Inamoto.
But it was a double substitution which resulted in Albion getting back into the game.
Nathan Ellington and Kanu took over from Campbell and Inamoto, and within 90 seconds had carved out the equaliser.
Kanu pushed the ball back into Ellington's path for the former Wigan man to blast his shot past Maik Taylor and secure a vital point.