From the Research
The workup of a felon on the thumb involves prompt clinical evaluation and intervention, with a focus on preventing complications such as palmar necrosis of the distal phalanx, as highlighted in a case report from 1. The initial step in managing a felon is to perform a thorough history and physical examination, noting the duration of symptoms, any preceding trauma, and assessing for signs of infection including erythema, swelling, pain, and fluctuance.
- Laboratory tests should include a complete blood count to evaluate for leukocytosis.
- X-rays are recommended to rule out osteomyelitis or foreign bodies. Treatment typically involves incision and drainage under digital block anesthesia using 1% lidocaine without epinephrine.
- The preferred incision is either lateral (avoiding the neurovascular bundles) or through the point of maximal fluctuance. After drainage, the wound should be irrigated with normal saline, packed lightly with iodoform gauze, and covered with a sterile dressing. Empiric antibiotic therapy should be initiated with dicloxacillin 500mg orally four times daily or cephalexin 500mg orally four times daily for 7-10 days to cover Staphylococcus aureus, the most common pathogen, as suggested by 2. For patients with MRSA risk factors, consider trimethoprim-sulfamethoxazole DS twice daily or clindamycin 300-450mg orally four times daily.
- Wound cultures should be obtained during drainage to guide antibiotic therapy. Follow-up within 24-48 hours is essential to assess response to treatment. Early intervention is crucial as delayed treatment can lead to complications including osteomyelitis, septic arthritis, or permanent functional impairment of the thumb, emphasizing the importance of prompt management as noted in 1. Although a study from 3 explores the role of piperacillin and tazobactam in combination with vancomycin against MRSA, this does not directly impact the initial workup and treatment of a felon on the thumb.