"Felon" is the medical term for an infection of the finger or thumb pulp (the fleshy area of the finger/thumb where your fingerprints are).

How does it happen?

It most commonly occurs after a small penetrating injury (a cut, splinter, scratch, spike, bite or snip) to the fingertip. Bacteria get into the pulp through this wound, multiplying to produce a tender, red, swollen infected finger tip. Pus forms under the skin and spreads throughout the pulp. The injury to the finger may have been on the front or back of the finger, and a felon may occur as a result of an untreated paronychia (nail fold infection).

How is it treated?

If a finger infection isn't settling quickly with antibiotics, elevation and immobilisation then you will need to be admitted to hospital and surgery is usually indicated to wash out the wound and drain any pus.

During treatment you will be advised to:

• keep your hand elevated at or above the level of your heart. This reduces swelling.
• keep your hand still. A plaster or fibreglass splint will be applied with a bandage to keep your fingers, hand and wrist still.
• take regular antibiotics. When you are in hospital these will usually be administered intravenously (through a "drip"). Once your condition is improving you will be able to take tablet or capsule antibiotics and go home.
• cease smoking, if you smoke. Smoking reduces the blood flow to the hand by 42%; if you smoke you reduce your ability to fight infection and to heal.
• take pain medications as required for the throbbing pain.

Should I seek early treatment?

Yes. In the early stages it can be possible to treat a felon successfully with tablet antibiotics, rest, elevation and immobilisation. Once your pain has become constant and severe it is unlikely that the infection will clear up without surgery and you need to see a surgeon urgently. If you have diabetes or a medical condition that affects your immune system you are at greater risk of a bad infection.

What type of surgery is performed?

Surgery is performed if you are thought to have an abscess (a collection of pus), contaminated wound or a foreign body (such as a splinter) in your fingertip. If you have a visible wound from your original injury this will be probed and washed. If there is pus in the finger pad an incision will be made to drain this. During surgery your surgeon will take swabs or tissue samples which are sent to the microbiology laboratory for testing, so that the type of bacteria can be identified and we can determine what type of antibiotics are best suited to the particular infection that you have. You may need more than one operation.

What are the risks?

It can be difficult to drain a nasty pulp infection, because the pulp has many interconnecting channels within it, which gives bacteria lots of different little areas to hide in. You may require more than one surgery. Early treatment is preferable for a quick and full recovery. If treatment is delayed and your infection is slow to clear up you are at risk of skin necrosis (skin death), septic arthritis (joint infection), osteomyelitis (bone infection) and tenosynovitis. One of the risks of surgery is that you may have altered sensation at the site of the incision (numbness, hypersensitivity or a feeling of unpleasantness); to avoid this, where possible the incision will not be made on the part of the pulp that is most frequently used to touch or hold objects.

What sort of bacteria cause a felon?

The most common bacterial cause is Staphylococcus aureus (Golden Staph), which is one of the most common bacteria found on the skin. Streptococci are also common causes. For this reason antibiotics like "flucloxacillin" or "cephalexin" are commonly prescribed for a felon, because they cover the most common bacteria. If your initial injury involved an unusual environment, like the ocean, a fish tank, a farmyard or a cat bite then the choice of antibiotic will need to take this into consideration.

What is involved in the recovery?

Speak with your doctor, as every situation is different. Generally speaking, you may need to be off work for 1-4 weeks, depending on the severity of your infection and the type of work that you do. During the first week you may need to keep your hand elevated in a sling and immobilised with a splint. You will see your surgeon approximately 5-7 days after you leave hospital, to check your wound and change your dressings. If you are able to work with a simple dressing on your finger (such as for office duties) you may be able to return to work 1-2 weeks after leaving hospital. If your job involves heavy work in a dirty environment you will need additional time off work.

If you develop a complication, such as infection of the bone, you may need to take antibiotics for at least 6 weeks and additional follow-up with X-rays will be required.