Diagnosis: Felon
The most likely diagnosis is a felon (Option A), which is an abscess of the distal pulp of the fingertip following a puncture wound from the hairdresser's tools. 1, 2
Clinical Reasoning
A felon presents as a swollen, painful fingertip pulp following penetrating trauma, which precisely matches this clinical scenario 1, 2. The key distinguishing features that confirm this diagnosis include:
- Location: The infection involves the "bulb" (pulp) of the thumb, which is the characteristic site for a felon 1, 2
- Mechanism: Direct puncture injury from occupational tools, which is the typical precipitating event 1, 2
- Intact nail bed: This rules out paronychia, which specifically involves the epidermis bordering the nail fold 1, 2
Why Not the Other Options
Paronychia (Option B) is excluded because it involves infection of the nail fold/epidermis bordering the nail, not the fingertip pulp 1, 2. The intact nail bed and pulp location make this diagnosis incorrect.
Onychomycosis (Option C) is a chronic fungal infection of the nail plate characterized by thickening, discoloration, and friable nail texture 3, 4. This develops over months, not acutely after trauma, and would not present as a swollen pulp.
Cellulitis (Option D) is a more superficial soft tissue infection that spreads diffusely through subcutaneous tissues 3. A felon is specifically a closed-space abscess of the fingertip pulp with characteristic anatomic involvement of the fibrous septa, making it a distinct entity requiring different management 1, 2.
Critical Management Considerations
Early felons (within 24-48 hours) may respond to elevation, oral antibiotics, and warm water soaks 1, 2. However, most felons require surgical incision and drainage to prevent complications 1, 2, 5.
Common pitfall: Delaying surgical drainage can lead to devastating complications including osteomyelitis of the distal phalanx, flexor tendon sheath infection, and even palmar necrosis requiring reconstructive surgery 6, 5. The closed-space anatomy of the fingertip pulp means infection spreads rapidly through fibrous septa and can extend proximally 6.
Immediate actions needed: Splinting in position of function, elevation, empiric oral antibiotics covering Staphylococcus aureus (the most common pathogen), and urgent surgical consultation if there is fluctuance, severe pain, or any signs of progression 1, 2, 7.