How concerned should I be about this small wound?

Yes, you should seek medical attention if it grows, first thing in the morning. Tonight (assuming you are in a time zone in the Americas) take an ink pen and draw a circle at the edge of the redness so you know how much it grew in how much time. Cellulitis tends to grow about a centemeter in 12 hours. If you have red streaks traveling up your arm go to the doctor now. Both things are very serious.

Thanks @JLeslie. Its 11:13pm and an ER trip seems crazy. My doc has Saturday clinics so if need be I can go tomorrow. The pen around the redness is a great idea.

I believe necrotizing facitius is not visible on the skin. Well, it might be at the site where the injury happened, but the pain would be beyond where it is hot and red most likely. You probably have a typical cellulitis. If you have the red streaks that can be blood poisoning.

Don’t be shy about going to emergency if you get very nervous, cat scratch fever many times needs IV medication if it progresses.

If it is very red and painful you should be seen soon. You may need an antibiotic.

One of my own cats bit me some years ago, I took her to the groomers for the first time for a summer shave as she was a huge, fluffy black kitty. She freaked out and sunk a fang into the soft part of my inner arm just below the elbow joint. It developed into a hole in my arm over about a week period and I needed an antibiotic to knock out the infection. I still have a scar, like a crater from her fang. It was very painful.

Claws carry lots of bacteria too.

Any particular reason why you googled necrotizing faciitis? It couldn’t have been your first instinct.

@lillycoyote Why do you ask that? I hope everyone knows about necrotizing faciitis.

Oh years ago when I had my daughter I had a bad infection in my c section wound that required 3 surgeries and lots of wound packing. My mom kept freaking about flesh eating bacteria, worrying that was the cause of my infection. I’m a bit of a germaphobe, so yes, it crossed my mind but wasn’t my first thought.

Cat scratch is nothing to take lightly.

Like @Coloma my mom suffered a bite/scratch from one of our beloved house cats a few years ago. Mom wound up needing a week of antibiotic IVs at the hospital, and in office surgery on her hand.

@JLeslie I ask that because, while I know about necrotizing facitis my first instinct upon getting a puncture wound from a cat would not be to google necrotizing facitis 1. because it’s relatively rare and 2. even rarer that it would arise from a puncture wound by a cat in someone who doesn’t have some preexisting condition making them more susceptible to necrotizing facitis, that’s why. There are much more likely infections that might be caused by a cat scratch or a bite or a puncture wound. I have had cats my whole life and none of them have ever killed me. You are more likely to be infected with something by a strange cat than one of your own or one you have been exposed to in the past. Though my aunt did get a bite from one of her cats that put her in the hospital for a couple of days and the cat had to be put down because of it. I’m not saying necessarily that this should be taken lightly but one should make decisions based on what the risks most likely are not on what is least likely.

Just do the diagnosis and everything will be fine.

Did you disinfect the wound when it happened (or at any point afterward)? That would be my first thought, to see if I could get rid of the infection that way. If it’s not better this morning, or worse, of course, I’d go see the doctor. Please keep us posted!

@lillycoyote Necrotizing faciitis can happen any time the skin is broken. Looking it up to check the symptoms seemed logical to me since God forbid she had (which I don’t think she does) it is an immediate accute emergency.

It is almost certainly an infection caused by bacteria the cat’s dirty claws have injected under your skin. Best to get it treated.