A felon is a distal digital pulp space pyogenic infection. Pus collects in spaces formed by the vertical septa anchoring the pad to the distal phalanx. It is characterized by severe pain, exquisite tenderness, erythema, and tense swelling of the distal digit. Visible pus or palpable fluctuance may be present. Complications include deep ischemic necrosis, osteomyelitis, septic arthritis, and suppurative tenosynovitis. The differential includes paronychia, herpetic whitlow, and traumatic hematoma.
Management and Disposition
Incision and drainage is necessary. To ensure complete drainage of the abscess cavity, all affected compartments should be entered. The packing of the abscess space is made with a small, loose-fitting wick to facilitate drainage. Oral antibiotics directed against gram-positive organisms should be used for 10 days, and the packing should be removed or replaced after 24 to 48 hours. Consider treatment for CA-MRSA in addition to standard coverage in highly endemic areas or in at-risk populations.
Incisions should be made on the ulnar aspects of the index, middle, and ring fingers and along the radial aspects of the thumb and small finger. Incisions should be made dorsal to the neurovascular bundle and not be extended proximal to the distal flexion crease.
“Hockey stick” and “fish mouth” incisions are associated with increased occurrence of unnecessary sequelae and are not recommended.
If there is radiographic evidence of osteomyelitis or concern for tenosynovitis, consultation with a hand surgeon is required.
Felon. Purulence, swelling, and erythema at the center of the palmar pad. (Photo contributor: Daniel L. Savitt, MD.)
Felon. Incision and drainage of a felon. (Reproduced with permission from Stone C, Humphries RL. Current Diagnosis & Treatment: Emergency Medicine. 8th ed. New York, NY: McGraw Hill; 2017.)