Felon

Background

• Subcutaneous pyogenic infection of the pulp space compartments of the distal finger
• Do not mistake for pulp erythema due to paronychia or herpetic whitlow
• Infection typically begins w/ minor trauma to dermis overlying finger pad (e.g. foreign body such as a splinter)
  • May spread to flexor tendon sheath, IP joint, or underlying periosteum

Felon

Clinical Features

• Red, tense, and markedly painful distal pulp space

Differential Diagnosis

Hand and finger infections

• Bed bugs
• Closed fist infection (Fight Bite)
• Hand cellulitis
• Hand deep space infection
• Hand-foot-and-mouth disease
• Herpetic whitlow
• Felon
• Flexor tenosynovitis
• Paronychia
• Scabies
• Sporotrichosis

Look-Alikes

• Digital mixoid cyst

Diagnosis

Workup

• X-ray to assess for foreign body
• Gram stain and culture (chronic infections may be caused by atypical organisms)

Evaluation

• Usually a clinical diagnosis

Management

Incision and drainage

Incision of felon.

• The incision should be made along the ulnar aspect of the index, middle, and ring fingers and along the radial aspects of the thumb and little finger.
• Number 11 blade is used to make incision on nonoppositional side of affected digit
• Start incision 5 mm distal to flexor DIP crease
• End incision 5mm proximal to nail plate border
• Bluntly dissect and explore wound until abscess is decompressed

no need for packing

• DO NOT perform a "fishmouth" incision since this may results in: Unstable finger pad, neuroma, and/or loss of sensation

Antibiotics

Indicated for felon associated with cellulitis Definitive treatment is drainage but antibiotic coverage for S. aureus and Strep with caution to identify Herpetic whitlow

• Cephalexin 500mg PO q6hrs daily x 7 days
• TMP/SMX 2 DS tablets PO q12hrs x 7 days
• Clindamycin 450mg PO q8hrs x 7 days
• Dicloxacillin 250mg PO q6hrs daily x 7 days

Disposition

• Discharge with followup in 2 days for wound check
• Refer to hand surgery only if systemically ill or concern for complicated infection
• Instruct pt to keep extremity elevated

See Also

• Hand and finger infections