What is a fingertip infection?
Fingertip infections can be of two general kinds: infections around the nail, called a paronychia, or infections in the fingertip pulp, called a felon. There are other kinds of infections of the hand; this page is only on infections of the finger tip, not the finger itself or the hand. Fingertip infections, either a paronychia or a felon, are different in some ways, due to the way that they spread, but they are treated in a very similar way. There are billions of bacteria on our skin all the time. This is normal. Usually, our body's defenses (intact skin, immune system, etc) are winning the battle and the bacterial get killed off when they enter the body. In the case of a fingertip infection, however, the bacteria start to win. This can happen because the bacteria get past our first line of defense, the skin. A typical way is for you to get a small cut or a small tear in the skin along the edge of the nail, called the cuticle. Biting a splitting cuticle or biting one's nails can cause this as well. Another kind of infection can be caused by the normal fungus on our skin. These develop more slowly and, when treated, resolve more slowly.
When the infections first start, the fingertip is just slightly tender, swollen, and red. Over the next few days, the fingertip gets worse in all three of these: it hurts like crazy (especially if it is bumped), it gets very swollen, and it gets very bright red. This tells you that the battle is going badly for you! The bacteria are winning, and you need a hand surgeon to help you win the battle.
A paronychia (which is Latin for "infection in the region of the nail") is an infection around the edge of the nail plate (the part that you cut with a fingernail clipper). Look at the photo above and you can see how the infection goes all around the edge of the nail, at the upper side of the picture (it does not go to the side where you cut the fingernail). See our page on paronychias.
A felon is an infection in the pulp space on the side of the finger with the fingerprint. See our page on felons.
Both of these infections have special aspects, due to how the fingertip is constructed. However, the course of the infection and the treatment is about the same, so I will talk about the stages of them both here.
The first stage of the infection
Infected fingers start out with the bacterial invading your tissues, and causing the generalized tenderness, swelling, and redness. This is called cellulitis, which is Latin for "infection of the cells". This can often be treated by only hot soaks and antibiotics. However, it can be very difficult to tell the two stages apart. You need to see a skilled hand surgeon.
The second stage of the infection
As the battle goes on and the bad guys start winning, the battle causes a pocket of pus (the white cells your body is using to fight the bacteria) to form. This is called an abscess. This needs both surgical drainage and antibiotics.