My dog ate some crab and now I am wondering

Most probably something is stuck in your dogs throat or mouth. But do refer to your vet. Similar thing happened to my lab a year ago. She ate a soft shelled crab and was coughing a few hours later. when we brought her to the vet they removed a large piece of the shell. Also they gave her something for alergies coz apparently srimps and crabs are not good for doggies.

Yes, your dogs had an allergy.Crabs are not advisable for dogs,it can cause allergy like chicken and shrimps.It can also damaged the coat of your dog.You should call a vet.I have a lots of dogs but I never let them eat another food,except for their dogfood.

What is probably more likely is that she has pieces of crab shell stuck in her throat, since dogs don't understand that the shell is not for eating. What you could do to start off is look inside the dog's mouth, all the way back, and see if you see any shell pieces that you could get out. If not, then they are either too far back, or perhaps just caused some irritation in the throat. She's probably wanting water to try to wash down whatever has irritated her. If her face and paws are not swollen, and there are no hives or other areas of swelling, and if she's not having any trouble breathing, that's probably the culprit. If she IS having any of that, then you should take her to your vet right away so they can give her an antihistamine injection.