If the infection is noticed and caught early enough, it may be one that can be treated with antibiotics and rest. Your hand surgeon will determine how to treat the infection after examining it, but you must visit your doctor as soon as you suspect infection. Severe problems can start in as little as a day or two unless the infection is treated with antibiotics, infected tissues are removed, and the wound is surgically drained. To determine the nature of the infection or the type of bacteria that is causing it, any fluids or pus draining from the site should be sent to a laboratory for testing.
A paronychia is an infection caused by bacteria that is located around the cuticle surrounding the fingernail (figure 1). If it is a case of acute paronychia, you will notice redness, swelling, and pain in the area, and it may produce pus if left untreated.
If caught early enough, paronychia can often be treated with antibiotics and soaking, but if it is the source of pus, additional steps may be needed. In more-advanced cases, the cuticle and nail may need to be lifted up and drained, or the infected area may need to be lanced by a hand surgeon.
If the paronychia is caused by a fungus and the cuticle is only mildly red and swollen with little or no discharge and slight tenderness, it is considered a case of chronic paronychia. People whose hands are often wet, such as dishwashers or bartenders, are likely to develop this condition. It can often be treated with special medication and with changes or elimination of the constant moisture that enables the fungus to grow. Sometimes the skin or other infected tissue needs to be surgically removed, and people who suffer from chronic paronychia often need lengthy treatment.
Felon infections are more serious and usually more painful than paronychia. A felon infection is located under the fingertip and often throbs. An infection of this type usually requires surgery to drain the infected site, and antibiotics are often used to treat the infection. If felon infection is not recognized and treated early enough, it can destroy the soft tissues at the fingertips and even the bone.
Herpetic Whitlow Infection
One viral infection that healthcare workers in particular are susceptible to, because of exposure to people who carry the herpes virus, is herpetic whitlow. This infection, which comes from the herpes virus, can appear anywhere on the hand, but usually shows up on the fingers in the form of tiny blood blisters that are painful. A herpetic whitlow infection can also cause numbness and is usually treated with medication for a period of weeks.
Septic Arthritis and Osteomyelitis Infection
Septic arthritis can result from a wound near one of the joints or from a nearby arthritic joint that drains and infects it. In a matter of days, if untreated, the bacteria causing the infection can destroy all the cartilage that lines the joint. To treat septic arthritis, antibiotics and surgery to drain the infection are used, and must be done promptly to prevent the infection from spreading to the bone in a condition called osteomyelitis. It may take more than one surgery to get rid of all the infected tissue, and many patients need weeks of intravenous antibiotics before treatment can be stopped.
Deep Space Infection
Deep space infections are those effecting deep areas of the hand. These spaces can become infected, usually from a puncture-type wound, and may show up in the thenar space, near the thumb, in the deep palmar space of the palm, or even in the webs between the fingers in a collar-button or web space abscess. Any infection in the deep spaces of the hand needs to be surgically drained by your hand surgeon, and if left untreated, can spread and even infect the wrist and forearm.
Tendon Sheath Infection
Any small cut or puncture in the middle of a finger can lead to an infection of the flexor tendon, especially if the wound is near a joint on the inside of the finger. An infection of the flexor tendon often causes the finger to become very stiff and can lead to the tendon becoming ruptured and destroyed. The infected finger is often stuck in a slightly bent position, stiff, and red, and swelling is common. The inside of the finger, near the palm, is frequently tender, and any attempt to straighten the finger out creates severe pain (figure 3). To treat a tendon sheath infection, a hand doctor will surgically drain the tendon sheath, and antibiotics will be given.
Atypical Mycobacterial Infection
The tendon sheath can also be infected by an atypical mycobacterium, though this is less common than an infection that comes from a cut or puncture. An infection of this type usually grows slowly, and while the infected finger may show swelling and become stiff, there usually isn't any pain or redness. To treat this type of infection, several months of special antibiotics are used, and surgery to remove the infected lining that surrounds the tendon may be required. Even after being treated, some remaining stiffness is common.
An atypical mycobacterial infection can infect other parts of the hand and isn't limited to the joints in the fingers. A common form of this is mycobacterium marinum, which can come from deep punctures from fish spines or from a contamination that comes from stagnant water, or from any other simple wound. The source of the contamination can either be a pond or puddle in nature, or can even come from a home aquarium.
It isn't always easy to identify the specific organism that is causing the infection, but that isn't necessary for the infection to be treated. Those who have an impaired immune systems are more likely than the general population to develop an atypical mycobacterial infection.
Bite Wounds Infection
Animal and human bite wounds are very common and can lead to an infection because of the high number of bacteria that live in the mouth. An infection that comes from a bite can be caused by any one of a number of bacteria. Click here to learn about the risk of bacterial hand infections caused by animal bites.
Streptococcus can be involved, as can staphylococcus, which results from a tooth going below the surface of the skin. Other organisms that are common in the mouth can cause other infections and may need other or extra antibiotics to be successfully treated. Human bites often produce eikenella corodens, and Pasteurella multocida arises from dog or cat bites.
In all bites, the wound is usually left open after being cleaned and treated to let any infection drain out. Since the bite can cause an infection in a deep structure like a joint or knuckle, the area of the bite needs attention. To treat the infection, it may be necessary for your hand surgeon to trim away any infected tissue, including any bones that may have been crushed. If the bite came from an animal, the possibility of rabies is very real and since it can lead to serious or even fatal results, very serious. The risk of rabies infection determines the treatment plan your doctor will provide, and, fortunately, reported human cases of rabies are rare. The chances of a domestic animal having rabies is small, and most cases come from wild animals such as skunks, bats, or other rodents.