What Is It, Causes, Appearance, Diagnosis, Treatment, and More
Author: Corinne Tarantino, MPH
Editors: Ahaana Singh, Lisa Miklush, PhD, RN, CNS
Illustrator: Jillian Dunbar
What is a felon finger infection?
A felon finger infection, commonly referred to as felon finger, is a painful infection affecting the soft tissue located on the pad of the finger, also known as the fingertip pulp. Felon finger often develops as a result of trauma (e.g. cut or scrape) to the soft tissue of the fingertip. A felon finger infection is usually painful and presents with redness and swelling.
What causes a felon finger infection?
A felon finger is most often the result of a bacterial infection that invades the finger after a penetrating trauma, such as a cut, scrape, splinter, or puncture wound, which usually occurs from something sharp and pointed creating a small opening in the skin. When there is a break in the skin of the fingertip, bacteria have the opportunity to grow and multiply there. The most common bacteria that causes felon finger is Staphylococcus aureus. In addition, felon finger may also be caused by the Streptococcus bacterial species. In other cases, untreated paronychia can also lead to felon finger. Paronychia is an infection around the nail beds that often occurs from nail trauma caused by nail biting, manicures, or artificial nails.
What are the signs and symptoms of a felon finger?
The primary signs and symptoms of felon finger are a swollen, red finger pad with intense, throbbing pain that is tender to the touch. Initially, an individual with felon finger may only present with redness on their finger, which is later accompanied by progressively increasing pain. In later stages of an infection, a moveable abscess, or a pus-filled lump, may appear. The abscess may spontaneously drain, providing temporary relief, but if left untreated, will likely reform. If the infection continues to progress without treatment, felon finger can lead to deeper infections in the bone (i.e. osteomyelitis) or tendons of the finger (i.e. pyogenic flexor tenosynovitis).
What does a finger felon look like?
Felon finger often presents with a red bump inside the tip of the finger. If an abscess has formed, the bump may be filled with pus and may appear slightly white or yellow. Oftentimes, a felon finger may be confused with a herpetic whitlow, which results from the herpes simplex virus and may also present with a small bump on the tip of the finger. However, with herpetic whitlow there is generally a multi-bubble-like appearance. In contrast, felon finger will generally have only one central area of infection.
How do you diagnose a felon finger?
Felon fingers are primarily diagnosed through a clinical examination of the finger and a review of medical history in order to rule out other potential infections. For example, a history of herpes may suggest herpetic whitlow instead of felon finger. Likewise, a recent splinter may indicate susceptibility to a felon finger. During clinical examination, the provider may assess the location of the redness, swelling, and pain in the finger. They may also check for abscess formation.In some cases, additional testing, such as wound cultures or imaging may be performed. A culture may be taken to test for the specific type of bacterial infection in order to determine the best course of antibiotic treatment. Ultrasound imaging may also be performed to identify the presence of an abscess.
How do you treat a felon finger?
If identified early, a felon finger will typically be treated with antibiotics. In general, the course of antibiotics will run 7–10 days and will usually treat both staphylococcal and streptococcal infections. Some possible antibiotics include trimethoprim/sulfamethoxazole, cephalexin, amoxicillin/clavulanate, or clindamycin. If the cause of the felon finger was trauma from a foreign body, the foreign body will need to be fully removed and a tetanus shot may be given as a preventive measure.In the case of abscess formation, incision and drainage will often be required. For deep abscesses, the incision will usually be made on the side of the finger. If, however, the abscess is closer to the surface of the skin, an incision may be made down the center of the finger pad. After incision and drainage, gauze is generally left in place for 24 to 48 hours and then changed daily for healing to occur. Follow-up appointments may be scheduled to ensure the felon finger is healing properly after treatment. Generally, no antibiotics are prescribed once drainage has occurred.
Can a finger felon heal on its own?
A felon finger cannot heal properly on its own and therefore requires adequate evaluation and treatment. If left untreated, the infection can spread deeper into the finger and cause several complications. In some cases, the swelling can block the blood supply and result in tissue death (necrosis) of the finger pad. In other cases, infection may spread deeper causing pyogenic flexor tenosynovitis or osteomyelitis. Therefore, it is important to seek treatment when a felon finger is suspected.
How do you treat a felon finger at home?
In some cases, if recognized early, a felon finger can be treated at home. A conservative approach is to treat the felon finger by soaking it in warm water and elevating it for about 10–15 minutes, three or four times a day. Elevation by resting the finger above the level of the heart can also prove beneficial. In addition, a provider may prescribe antibiotics to be taken at home.
What are the most important facts to know about felon finger infections?
Felon finger is a painful bacterial infection on the fingertip pulp. The cause of felon finger is often a cut or scrape on the finger that allows for bacteria, such as Staphylococcus aureus, to enter and multiply. The felon finger initially looks like a red bump and can progress to an abscess filled with pus. Early treatment with antibiotics is effective at removing the infection. If a felon finger is suspected, it is important to receive medical advice early to avoid more invasive treatments or complications.
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Resources for research and reference
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Germann, C.A. (2020). Nontraumatic disorders of the hand. Tintinalli, J. E., et al. (eds.). Tintinalli's Emergency Medicine: A Comprehensive Study Guide (9 edition). New York: McGraw-Hill.
Lifchez, S. D. & Cho, B. H. (2019). Surgery of the hand and wrist. Brunicardi, F, et al. (eds.). Schwartz's Principles of Surgery (11 edition). New York: McGraw-Hill.
Miller, L.S. (2019). Superficial cutaneous infections and pyodermas. Kang, S. et al. (eds.). Fitzpatrick's Dermatology (9 edition). ew York: McGraw-Hill.
Nardi, N. M., McDonald, E. J., & Schaefer, T. J. (2020). Felon. In StatPearls. Retrieved January 15, 2021, from https://www.ncbi.nlm.nih.gov/books/NBK430933/Rerucha, C. M., Ewing, J. T., Oppenlander, K. E., & Cowan, W. C. (2019). Acute Hand Infections. American Family Physician, 99(4): 228-236.