Today a Golden Retriever presented with a rapidly growing mass under her jaw. It was not painful or inflamed, but when I took some fluid out of it with a needle, I saw very large numbers of bacteria and white blood cells. I suspected that this abscess could be due to a foreign body or infected salivary gland, so I sedated her and made an incision over the mass. After blotting away the fluid that came out of it, I was relieved to see this plant awn inside.
This 1 cm seed pod can penetrate tissue, and due to its shape, can't back out. Although plant awns are more common out west, we see our fair share of them here. In fact, I once saw 2 dogs, 2 days in a row, with plant awns lodged in the mucus membranes of their left eyes. And they were from the same family!
I believe this awn migrated from the mouth rather than through the skin for three reasons: First, the mucus membranes of the mouth are much thinner. Second, I could actually feel a thin tubular structure leading to the abscess. This was the tract that the awn followed before it was walled off by the body and led to the abscess. Finally, the type of bacteria in the abscess were typical of oral bacteria, and not the skin.