Acute Paronychia

Aka: Acute Paronychia, Paronychia, Perionychia

1. See Also
   1. Chronic Paronychia
   2. Hand Infection
2. Definition
   1. Superficial infection of distal phalanx along nail edge
   2. Affects perionychium (Epidermis at nail border)
3. Pathophysiology
   1. Disrupted seal between nail fold and nail plate
   2. Mechanisms of Acute Paronychia
      1. Local penetrating trauma
      2. Nail biting
      3. Finger sucking
      4. Aggressive manicure
      5. Hang nail
      6. Artificial nail placement (sculptured nails)
      7. Dermatitis (e.g. Pemphigus Vulgaris)
4. Etiology: Polymicrobial in most cases
   1. Trauma related (most common)
      1. Staphylococcus aureus (common)
   2. Oral flora related from nail biting or sucking
      1. Streptococcus Pyogenes (common)
      2. Pseudomonas pyocyanea
      3. Gram Negative Bacteria (e.g. Proteus vulgaris)
   3. Other causes (Anaerobes)
      1. Bacteroides
      2. Fusobacterium nucleatum
5. Symptoms
   1. Onset 2-5 days after trauma
   2. Local pain at perionychium (Eponychium)
6. Signs
   1. Early: Perionychial inflammation
      1. Local redness
      2. Swelling
      3. Tenderness at nail edge to palpation
      4. Discolored nail
   2. Late: Complicated infection
      1. Abscess at perionychium
      2. Nail bed infection
      3. May elevate nail plate
7. Signs: Digital Pressure Test
   1. Indication: Diagnostic for early Paronychia before abscess is clearly demarcated
   2. Technique
      1. Patient opposes thumb and affected finger (applying pressure to pulp at finger tip)
   3. Positive test
      1. Abscess becomes demarcated with blanching
   4. Reference
      1. Turkmen (2004) Br J Plast Surg 57:93-4
8. Differential Diagnosis
   1. Chronic Paronychia
   2. Felon
   3. Herpetic Whitlow
   4. Cellulitis
   5. Tuft Fracture
   6. Psoriasis
   7. Reiter Syndrome
   8. Contact Dermatitis
   9. Maceration from excessive moisture
9. Labs
   1. Consider wound culture in severe cases to identify MRSA
10. Management: General measures
    1. Soak 3-4 times daily for 15 minutes each
       1. Warm water or
       2. Burow's Solution or
       3. Acetic acid soaks (1:1 vinegar in water)
    2. Splint affected finger
    3. Tetanus prophylaxis
    4. Incision and Drainage if abscess pocket is delineated (see below)
    5. Antibiotics: Topical in early, mild cases
       1. Bactroban twice daily for 5-10 days or
       2. Gentamicin ointment three times daily for 5-10 days
       3. Neomycin ointment
          1. Indicated for pseudomonal Paronychia (green discoloration, moist environment)
       4. Consider with adjunctive Topical Corticosteroid (medium to high potency)
          1. Wollina (2001) J Eur Acad Dermatol Venereol 15:82-4
    6. Antibiotics: Systemic in persistent, moderate to severe cases
       1. History may direct specific antibiotics
          1. Traumatic cause in region where MRSA is common
          2. Nail biting cause directs antibiotic coverage for oral flora
          3. Green discoloration (esp repeat trauma in chronically moist environments) may direct pseudomonas coverage
       2. First line (for Staphylococcus aureus if trauma is source as opposed to oral flora)
          1. Cephalexin (Keflex) or
          2. Dicloxacillin
       3. Second Line (for Gram Negatives and Anaerobes if oral flora source suspected)
          1. Clindamycin
          2. Amoxicillin-Clavulanate (Augmentin)
          3. Trimethoprim Sulfamethoxazole (Septra)
11. Management: Incision and Drainage
    1. Anesthesia
       1. Digital Block (Metacarpal Block)
    2. Contraindications
       1. Herpetic Whitlow
    3. Technique 1
       1. Identify blanched skin over abscess (may use digital pressure test as above)
       2. Puncture abscess with #18 gauge needle in multiple sites to allow drainage
    4. Technique 2
       1. Digital anesthesia block is required
       2. Pass #15 or #11 scalpel blade passed between nail and nail fold
          1. Abscess area should be clearly demarcated by overlying blanching of skin
          2. Direct blade away from nail
          3. Avoid entering through the Eponychium
          4. Avoid injury to cuticle
       3. May need to remove part of nail to expose infection
          1. Indicated for subungual abscess
       4. Irrigate wound
       5. Larger wounds could be packed with small plain gauze
12. Prevention
    1. Avoid nail trauma from nail biting, picking or sucking
    2. Do not trim or remove cuticles
    3. Keep finger nails clean and dry
13. References
    1. Brook (1990) Ann Emerg Med 19:994-6
    2. Hochman (1995) Int J Dermatol 34:385-6
    3. Jebson (1998) Hand Clin 14:547-55
    4. Rigopoulos (2008) Am Fam Physician 77:339-48
    5. Rockwell (2001) Am Fam Physician 63(6): 113-6