Like virtually every part of the human body, the hand is vulnerable to infections. The physical barrier of our skin combined with the constant defensive action of our immune system allow us to live in harmony with the billions of bacteria that exist in and around us. On occasion, the defenses can be broken down and bacteria are able to invade and multiply in unwanted areas The two most common paths to infection are by direct entry through a wound in the skin or by traveling through the blood stream, delivering bacteria from one location to another.
One common example of direct entry is animal bites. Cat bites are a frequent cause for a trip to the emergency room. Cat teeth are sharp and narrow, delivering bacteria deep into the tissues where they begin to multiply. The small size of the punctures allows the wounds to close quickly, trapping the bacteria inside and potentially creating a pocket infection known as an abscess. It is not uncommon for a serious cat bite infection to require hospitalization, intravenous antibiotics, and even surgical opening (drainage) of the abscess.
Not all direct entry infections are from trauma. A very common finger infection occurs around the base of the fingernail. The normal bacteria that live on our skin can sometimes find entry between the nail and the skin and start to multiply. This type of infection, called a paronychia, usually causes pain, redness and swelling of the skin around the margins of the nail. In some cases, a small collection of pus can sometimes be seen under the skin or under the nail. Treatment typically includes drainage of the pus and a course of oral antibiotics.
Infections that arise by travel through the blood stream often occur unpredictably. An ordinarily healthy individual can show up in the emergency room with hot, swollen finger with no known wound or injury. In fact, in many cases the original source of the bacteria is never clearly identified.
Although everyone is potentially susceptible to infection, there are certain medical conditions that increase the risk. Diabetes and rheumatoid arthritis are examples where the immune system is compromised and infections are more common.
If a hand infection is suspected, the most import first step is to quickly seek evaluation by a qualified health care professional. Redness, swelling, warmth or red streaking in the neighboring area are all local warning signs of a potentially serious infection. Fever, chills and sweats are more general warning signs.
Prompt evaluation, potentially including blood tests and cultures, is the best route to recovery with the fewest complications. One should not rely on topical antibiotic ointments since they have limited ability to penetrate under the skin. Antibiotics left over from other infections should never be used since they may or may not be directed at the type of bacteria that is currently the issue.