Finger infections

Common finger infections include paronychia, felon, and herpetic whitlow. A paronychia is an acute or chronic soft tissue infection around the nail body. Acute infections are typically bacterial in origin and usually occur after minor trauma. Chronic paronychia infections have a multifactorial etiology, often related to repeated exposure to moist environments and/or skin irritants, and may be accompanied by secondary fungal infection. The diagnosis of paronychia is based on clinical signs of inflammation. A bacterial culture or fungal stain can confirm the causative pathogen. Treatment of acute paronychia usually involves antibiotics, while chronic paronychia is treated with topical steroids and antifungal therapy. Complications include nail dystrophy or felon.

Felon is an infection of the distal pulp space of the fingertip. While the cause is often unknown, minor trauma most commonly precedes infection. It is a clinical diagnosis based on the presence of local pain, swelling, induration, and erythema. Early stages of felon may be managed conservatively with analgesics and antibiotics. Later stages require incision and drainage. Complications include fingertip soft tissue necrosis and osteomyelitis.

Herpetic whitlow is discussed in herpes simplex virus infections.

• Definition: soft tissue infection around a fingernail
• Epidemiology
  • Most common hand infection in the US
  • Sex: ♀ > ♂ (3:1)

• Definition: distal pulp space infection of the fingertip
• Etiology
  • Wooden splinters, minor cuts, paronychia → cellulitis of fingertip pulp → abscess formation and edema
  • Pathogen: Staphylococcus aureus (most common)
• Clinical features
  • Commonly involves the thumb and index finger
  • Localized edema at the fingertip; associated with pressure, prickling, or throbbing pain
• Diagnostics
  • Clinical diagnosis
  • Culture wound fluid: to identify the causative pathogen
• Treatment
  • Early oral antibiotic treatment, decompression , and elevation should improve the condition in 12–24 hours.
  • Tetanus prophylaxis
  • If severe or blood flow is compromised: IV antibiotics and surgical drainage
• Complications: necrosis, osteomyelitis, tenosynovitis, septic arthritis

• Definition: bacterial infection of the distal periungual tissue
• Etiology: infection with group A hemolytic streptococci; less commonly also with Staphylococcus aureus
• Clinical features
  • Development of a single, purulent blister (1–2 cm)
  • Located on the anterior palmar fat pad near the nail folds
• Diagnostics: Gram stain of blister contents shows gram-positive cocci.
• Treatment: incision and drainage PLUS oral antibiotics
• Complications: separation of nail from the nail bed; permanent nail dystrophy

1. Relhan V, Goel K, Bansal S, Garg VK. Management of chronic paronychia. Indian J Dermatol. 2014; 59 (1): p.15-20. doi: 10.4103/0019-5154.123482 . | Open in Read by QxMD
2. Rockwell PG. Acute and Chronic Paronychia. Am Fam Physician. 2001; 63 (6): p.1113-1117.
3. Phillips BZ. Nail Anatomy. Nail Anatomy. New York, NY: WebMD. http://emedicine.medscape.com/article/1948841-overview. Updated: September 12, 2013. Accessed: February 28, 2017.