tremondous swelling in face after root canal

[April2]

Just wondered if anyone might have an idea what's going on here. My husband had a root canal done on Friday. They gave him some penicillin and sent him home. That night he started to get a lot of swelling in his face. He did have a lot of infection and they could not complete the root canal because there was still a lot of infection, so they told him to come back this week and they would finish.
Last night I took him to the ER because he was so swollen he looked like Santa Clause in the face! He said he could barely swallow. We were wondering if he had a reaction to the penicillin or if the swelling was from the root canal? The doctor in the ER said he wasn't sure it was a reaction to the penicillin because he didn't get a rash or anything. I didn't think you had to necessarily get a rash. In any case, the doctor did go ahead and give him an antihistimine (Benadryl) and waited 30 minutes to see if that would help. There was still swelling but my husband did say it seemed as though he could swallow better.
My question is, was the facial swelling (and tongue) a normal reaction to the root canal or does it sound more like he had a reaction from the penicillin?
The doctor did prescribe a different antibiotic but how will we know now what caused all the swelling? Anybody have any idea? Is there anybody else out there who is allergic to penicillin who can tell me what kind of symptoms would be from that?
It just seemed like an awful lot of swelling, more than you would expect. Thanks!

[kblue2000]

Agreed..sounds like massive infection.

[love1221]

The swelling may have been from the procedure.  If there was a lot of infection, then essentially what they did was pretty much get in there and stir everything up.  I'm doubting that it was the penicillin, I think that he would have gotten a rash as well as the swelling.