Felon & Paronychia

Anatomy

Illustration by Dr. Lisa Bryski

The nail organ adds stability to the fingertip. The nail plate is made of keratin where the growing portion is under the proximal eponychium or cuticle. Perionychium or tissue surrounding the nail is comprised of hyponychium, eponychium and paronychium. Infection deep to the the eponychium and the lateral nail fold are termed paronychia.³

The fingertip pulp is a closed sac with a connective tissue framework separated by fibrous vertical septae. These septa span the area from the periosteum of the distal phalanx to the epidermis. A felon is infection of the pulp of the distal end of the finger.¹

CLASSIC PRESENTATION

Paronychia

Acute paronychia presents with pain, nail fold tenderness, erythema, and swelling. Exam demonstrates fluctuance and nail place discolouration (Pseudomonas if green).

Chronic paronychia presents with recurrent bouts of low-grade inflammation. Exam shows nail plate hypertrophy, blunting, and prominent transverse ridges on nail plate.²

Felon

Often caused by penetrating injury such as blood glucose needlestick or splinters. The infection can spread from paronychia. 50% of patients will have no history of injury. Infection in these cases is thought to be bacterial contamination of the fat pad through eccrine sweat glands.

Classic symptoms include: severe throbbing pain to fingertip often associated with erythema, swelling and tenderness. These are deep infections and can present with pain and moderate swelling only, without evidence of underlying pus.

⁴

Clinical Tip: Infection does NOT extend proximal to DIP flexion crease unless flexor tendon sheath/joint involved.

DIAGNOSIS

The diagnosis is primarily clinical. However, practitioners should consider radiographs to rule out foriegn body or fracture if history of trauma.

MANAGEMENT

Acute Paronychia

Acute paronychia can be managed conservatively with warm soaks, oral antibiotics (Amox/Clav, Clindamycin) and avoidance of nail biting if the patient presents with swelling and no fluctuance.

Incision and drainage may be required with partial/total nail bed removal followed by antibiotics if there is concern for an abscess collection. If an incision and drainage is performed, obtain a sample for culture & sensitivity.

To perform an incision & drainage:

soak the patients finger to soften the eponychium.
Advance a No. 11 scalpel under the eponychium parallel to the nail with the blade pointing away from the center of the nail.
Open the lateral nail fold and bluntly elevate the eponychial fold to evacuate the exudate.⁵

Chronic Paronychia

Chronic paronychia is managed non-operatively with warm soaks, avoidance of finger biting/sucking, and topical anti-fungals, which is the mainstay of treatment. The most common cause of chronic paronychia is Candida especially in immunocompromised patients.

Operative management with marsupialization (excision of dorsal eponychium down to level of germinal matrix) is second line treatment. This is combined with nail plate removal and the wound is left to heal by secondary intention. This is usually performed by a hand surgeon.⁵

Felon

If presenting early, there may not be an abscess to drain. Therefore, practitioners may elect to treat with oral antibiotics, warm compresses and observation. Antibiotic coverage for S. aureus (most common), gram negatives in immunosuppressed and Eikenella in diabetics who bite their nails.

If the patient has a drainable collection, perform an incision and drainage and provide IV antibiotics.

Mid-lateral approach

o Indicated for deep felons with no foreign body and no drainage

o Incision on ulnar side of digit 2-4 and radial side for thumb and digit 5

o Remember to avoid the neurovascular bundle

Volar longitudinal approach

o This approach is discouraged as it leads to increased sensitivity with touch and pinch where the scar form

o Reserve for superficial felons, foreign body penetration or visible drainage

o Remember to avoid the insertion of the flexor tendon at the proximal portion of the distal phalanx

Debridement – generally done by a hand surgeon in the OR

o Avoid violating flexor sheath/DIP

o Break up septa to decompress infection

o Gram stain and culture (prior to antibiotics)

o Gauze wick

o Post op – routine dressing changes⁵

⁵

Clinical Tip: Avoid fish-mouth incision (risk of unstable finger pulp/vascular compromise) and double longitudinal/transverse incision (see below)

References

Miller, M. D., Hart, J., & MacKnight, J. M. (2019). Essential Orthopaedics E-Book. Elsevier Health Sciences.
Piraccini, B. M. (2014). Nail disorders: a practical guide to diagnosis and management. Springer.
Leggit, J. (2017). Acute and Chronic Paronychia. American Family Physician Journal. 96(1):44-51
Rerucha, C., Ewing, J., Oppenlander, K., & Cowan, W. (2019) American Family Physician Journal. 99(4):228-236.
Roberts, J. R., Hedges, J. R., & Sener, S. (2005). Clinical procedures in emergency medicine.

Page updated

Google Sites

Report abuse