Visual Diagnosis

Case: A 12-year-old boy presents with an intensely painful finger pad. Mild redness and swelling are noted at the site, which extend to the lateral surface of the thumb. The patient denied any known trauma to the affected digit.

Diagnosis:

This patient has felon.

A felon is a digital pulp abscess located within the volar soft tissues, which are comprised of small compartments separated by septa. Because of the proximity to the periosteum of the distal phalanx, spread of infection can result in osteomyelitis. The thumb and index finger are the digits most commonly affected. A puncture wound or an acute untreated paronychia are common preceding events. Staphylococcus aureus is the most common bacterial cause, though coverage for methicillin-resistant S aureus (MRSA) should be considered. Consultation with a hand surgeon is recommended.

Clinical Practice Pearls:

• Radiographs are used to rule out foreign body or bony involvement.


• Treatment usually requires incision and drainage. Though there are several options for incision, the longitudinal incision is preferred. After performing a digital block, a longitudinal incision 3 to 5 mm from the distal interphalangeal joint is made with a number 11 scalpel blade through the dermis over the area of maximal tenderness. The incision is carefully enlarged with a hemostat while leaving the septa intact to allow drainage once the abscess is located. The area is irrigated, and wick is then placed to keep wound edges separated and allow further drainage. A bulky dressing and forearm splint should be placed, with close follow-up arranged within 24 to 48 hours.


• A first-generation cephalosporin or anti-staphylococcal penicillin is recommended. Obtaining cultures may modify therapy, especially if positive for MRSA.

Further Reading:

• Clark DC. Common acute hand infections. Am Fam Physician. 2003;68(11):2167-2176.


• McDonald LS, Bavaro MF, Hofmesiter EP, et al. Hand infections. J Hand Surg Am. 2011;36(8):1403-1412.

• Babcock-Cimpello L, Deutsch RJ, Dixon CA, et al. Illustrated techniques of pediatric emergency procedures In: Fleisher GR, Ludwig S, eds. Textbook of Pediatric Emergency Medicine. 6th ed. Pennsylvania: Lippincott, Williams, & Wilkins; 2010:1813.