Overview
The course of most hand infections depends on anatomic, local and systemic factors, bacterial virulence and inoculum size. Anatomic factors that determine penetration, localization and spread include the thin skin and subcutaneous layer over tendons, bones and joints; the closed space of the distal digital pulp; the closeness of the flexor sheath to bone and joint; the proximal extent of the flexor sheath into the palm, connecting with the radial and ulnar bursae; and the thenar and midpalmar spaces and the space of Parona above the wrist. Treatment depends on identifying the organism, the anatomic area involved and the host's comorbidities. Surgical drainage and debridement of necrotic tissue are often required, and antibiotics alone may be insufficient. (Campbell)
Surgical site infections are uncommon after clean, elective hand surgery (under 1% in a database of 44,305 outpatient procedures). In a study of 516,986 clean elective hand procedures, prophylactic antibiotics made no difference in postoperative infection (1.5% vs 1.4%). Routine prophylaxis is generally unnecessary, particularly for short soft-tissue procedures such as carpal tunnel or trigger finger release. (Campbell)
Risk Factors and Differential Diagnosis
Local factors: extent and nature of soft-tissue damage; amount and virulence of contamination; type and amount of foreign material.
Systemic factors: malnutrition, alcoholism, IV drug use, diabetes, rheumatoid arthritis, gout/pseudogout, long-term corticosteroids, chemotherapy and anti-TNF drugs, immunosuppression after transplant, HIV.
Mimics of infection (Box 84.2): gout, pseudogout, acute calcium deposition, pyogenic granuloma, insect bites, pyoderma gangrenosum, foreign bodies, herpetic lesions, metastatic lesions, silicone synovitis, rheumatoid arthritis, nonspecific tenosynovitis, reactions to IV drugs, Sweet syndrome, aseptic neutrophilic dermatosis. (Campbell)
Diagnosis and Organisms
Determine the location, extent, swelling, lymphangitis, lymphadenitis and joint involvement. Fluctuance can be hard to identify in the hand. Radiographs show bone injury; radionuclide scans may show bone infection; MRI and ultrasound may localize an abscess. Obtain CBC, CRP and ESR, but these markers alone are inadequate: fewer than half of patients with finger infections have elevated CRP.
Send any fluid or tissue for Gram stain, crystals, culture and sensitivity (aerobic, anaerobic, and mycobacterial and fungal cultures when needed).
Consider mixed flora. S. aureus is the most common organism in community-acquired hand infections, and community-acquired MRSA is the most common cause of culture-positive hand infections in the United States. About 80% or more of swab cultures grow multiple organisms, whereas tissue specimens may yield a single organism in about 75%. Others: streptococci, enterobacteria, Pseudomonas, enterococci, Bacteroides. Specific exposures: Pasteurella multocida (cat and dog bites), Eikenella corrodens (human bites), Aeromonas hydrophila (fresh water), mycobacteria, Haemophilus influenzae (children 2 months to 3 years). (Campbell)
Antibiotic Principles (Campbell)
Traditional choices are a penicillinase-resistant penicillin or a cephalosporin, but MRSA prevalence must guide the choice. Add Gram-negative coverage in high-risk settings (IV drug users, contaminated farm or outdoor wounds).
Outpatient MRSA options: trimethoprim–sulfamethoxazole, doxycycline or minocycline, linezolid; clindamycin (resistance is increasing, from 4% to 31% over 2005–2014 in one study of 815 hand infections, with levofloxacin resistance rising from 12% to 56%). Vancomycin or daptomycin IV for serious cases.
A protocol of early, aggressive incision and drainage plus IV antibiotics shortens hospital stay and reduces complications. Failure to recognize polymicrobial infection and inadequate debridement are frequent causes of poor results.
After surgical drainage of simple hand infection, one comparison found no difference in outcomes with or without antibiotics.
General Technique 84.1: Incision and Drainage of Hand Infection (Campbell)
Use general anesthesia or a distant regional block. Local anesthetic may not work in septic tissue, may spread infection and adds swelling.
Use a tourniquet, but elevate the hand for 3 to 6 minutes before inflating it, without exsanguinating with an elastic wrap (which could spread infection proximally).
Make the incision for the specific infection.
After skin incision, always spread deeper structures bluntly to avoid injuring nerves, vessels and tendons, which are hard to see in swollen, infected tissue.
Irrigate copiously. Rather than primary closure, it is probably safer to return to the OR in 3 to 5 days for secondary closure. Cover any joints or flexor tendons exposed by skin necrosis at once. In most cases leave the wound open.
Postoperative care: bulky gauze dressing, a splint with the wrist in about 30 degrees of extension, MP joints in 60–70 degrees of flexion, IP joints in full extension and the thumb palmar abducted and opposed. Elevate continuously. Start active digital motion early. First dressing change at 24–48 hours, then daily or every other day, with therapist-supervised whirlpool dressing changes. Close secondarily when drainage has ceased and healthy granulation appears (a skin graft or flap is only needed if a skin slough occurred).
Specific Infections
Paronychia (Campbell)
Bacteria enter the nail fold (eponychium), associated with a hangnail or poor nail hygiene. In three studies (61 patients), 25% were anaerobic, 25% aerobic and 50% mixed.
Diagnosis: pain, redness, swelling and possible fluctuance at the nail fold.
Early treatment: warm water or chlorhexidine soaks, with or without topical or oral antibiotics. Drain any abscess. Antibiotics after drainage are probably unnecessary in most cases.
Abscess on one side: incise, angling the knife away from the nail to avoid the nail bed (which leaves a ridge). Under one corner of the nail root: remove that corner. If it has tracked to the other side beneath the nail: second incision, fold the skin back proximally and excise the proximal third of the nail. Pack loosely with iodoform gauze for 48 hours.
Swiss roll technique: elevate the nail fold and reflect it proximally over a nonadherent dressing, secured with nonabsorbable suture. If clean at 2–3 days (acute) or 7–14 days (chronic), unroll it. It keeps the nail plate and heals quickly.
Herpetic whitlow (HSV-1 or -2) can mimic bacterial paronychia, with clear vesicles, and is self-limiting over 3–4 weeks without surgical treatment. Immunocompromised patients receive antivirals (acyclovir, valacyclovir, famciclovir or foscarnet).
Chronic paronychia occurs with prolonged water exposure and is more like a dermatitis from environmental exposure. Treat with activity modification, oral antifungals (terbinafine, itraconazole) and topical steroids or tacrolimus. If that fails, eponychial marsupialization (Keyser and Eaton; Bednar and Lane, Technique 84.2): excise a 3-mm crescent of skin parallel to the eponychium from the radial to ulnar border, remove thickened tissue, remove the nail if irregular, and cover with Xeroform. Oral antibiotic (cephalexin or erythromycin) for 2 weeks, with peroxide soaks and chlorhexidine washes from postoperative day 3.
Felon (Campbell, Technique 84.3)
An abscess in the distal pulp, divided into tiny compartments by fibrous septa from skin to bone, so swelling quickly causes severe pain. S. aureus is the most common organism. It can spread to the periosteum (osteomyelitis), the nail fold or proximally into the flexor sheath.
Early presentation can be treated with rest, elevation, warm soaks and antibiotics (cover MRSA empirically).
Drainage:
If the abscess points volarly with necrotic skin, excise the necrotic skin.
A distal pulp abscess pointing toward the fingerprint whorl is drained through a vertical incision beginning distal to the skin crease, precisely in the midline to avoid the lateral digital nerve branches.
A deep abscess partitioned by septa: longitudinal incision, usually away from the contact surface of the finger, cutting through the partitions.
Keep the incision dorsal to the tactile surface and no more than 3 mm from the free edge of the nail. Use blunt dissection with small scissors tips to break septa. A J-shaped incision is enough. A fish-mouth incision is slow to heal and scars painfully.
Irrigate and pack with iodoform or sterile gauze.
Splint and elevate, change the bandage at 24–48 hours, then saline soaks. Diabetic or immunosuppressed patients may end with amputation.
Deep space infections (Campbell Table 84.2, Technique 84.4)
Deep spaces: interdigital web spaces, midpalmar, thenar, hypothenar, space of Parona and the dorsal subaponeurotic space. They are now rare because adjacent infections are controlled by antibiotics, and usually arise from spread of purulent flexor tenosynovitis.
Web space (collar-button abscess): adjacent fingers held abducted, with dorsal swelling and volar tenderness. Drain both dorsally and volarly: a dorsal longitudinal incision between metacarpal heads and a palmar one beginning distal to the distal palmar crease. Do not incise the web, and avoid crossing palmar creases at right angles.
Midpalmar space: loss of palmar concavity, marked palmar tenderness, painful motion of the long and ring fingers, and a swollen hand "like an inflated rubber glove." Drain through a curved incision at the distal palmar crease in line with the long finger toward the hypothenar eminence, entering the space on either side of the ring flexor tendon with a blunt hemostat.
Thenar space: thumb web swelling, index finger held flexed, painful thumb adduction or opposition (a "pantaloon" abscess if the first dorsal web is involved). Drain through a curved incision in the thumb web parallel to the first dorsal interosseous, or along the thenar crease (avoid the recurrent motor branch of the median nerve). Use blunt dissection.
Parona space: pain with passive finger flexion, possibly acute carpal tunnel syndrome. Use a palmar forearm incision just proximal to the wrist crease or through the floor of the FCR sheath, avoiding incisions directly over flexor tendons and median nerve.
Dorsal subaponeurotic space: dorsal swelling, painful finger extension. One dorsal longitudinal incision (or two over the second metacarpal and between the fourth and fifth, each 2–3 cm), blunt dissection, and a drain if there is dead space.
After drainage, irrigate, apply nonadherent gauze and a bulky dressing, and splint. Healing by secondary intention is usually satisfactory.
Flexor tenosynovitis (Campbell, Techniques 84.5 and 84.6)
Usually from a puncture wound near a flexor crease (S. aureus, sometimes Streptococcus). The four cardinal signs: tenderness over the sheath (the most significant), rigid flexed posture, pain on passive extension, and fusiform swelling.
If suspected early (symptoms under 48 hours), immediate antibiotics and splinting may abort spread, with close follow-up and a low threshold for admission. If gross pus is aspirated from the sheath, surgical drainage is indicated. Avoid needle aspiration through cellulitic tissue (risk of inoculating the sheath).
Sheath pressures can exceed 30 mmHg and render tendons ischemic, so delay risks tendon necrosis, adhesions and stiffness. Subcutaneous purulence and ischemic changes are linked to poorer outcomes (amputation rates of 8% and 59%, respectively).
Closed irrigation (modified Neviaser): tourniquet without exsanguination. Expose the proximal sheath at the A1 pulley through a transverse incision parallel to the distal palmar crease. Open the sheath proximal to the A1 pulley, swab fluid for culture. Make a second incision at the distal midaxial region or transversely over the distal flexion crease and open the sheath distal to the A4 pulley. Pass a 16- or 18-gauge catheter from proximal to distal for 1.5 to 2 cm and irrigate with saline until clear. If radial or ulnar bursa is involved, place a second catheter or drain and open the bursa proximally near the wrist. Postoperatively irrigate with 30 mL saline every 2 hours for 24 to 48 hours. The author of this chapter prefers returning to the OR for persistent symptoms instead of continuous catheter irrigation, because continuous irrigation did not improve outcomes.
Open drainage is for advanced infection with tendon and sheath necrosis. Use two incisions: midaxial on either side of the finger (dorsal to the neurovascular bundles), opening the sheath at the cruciform pulleys while preserving the annular pulleys, plus a palmar incision over the A1 pulley. Debride the flexor tenosynovium and bursae and leave the wounds open. Healing and rehabilitation are prolonged and full motion may not return.
Septic arthritis of the wrist and finger joints (Campbell)
About 25% of upper-extremity septic arthritis occurs in the wrist. S. aureus is the most common organism (almost 40% MRSA in reports). Ninety-day perioperative mortality over 20% has been reported regardless of treatment, reflecting comorbidities.
Prompt irrigation and debridement with antibiotics. Open arthrotomy through a dorsal approach can include the radiocarpal, ulnocarpal, midcarpal and DRUJ. Arthroscopic washout gives similar outcomes with fewer operations and shorter stays, except when there is postoperative infection, prior wrist surgery, osteomyelitis, pus outside the joints or an inaccessible joint.
Finger joints may be opened dorsally (PIP between central slip and lateral bands; DIP between terminal slip and collateral ligament), irrigated and left open, then closed secondarily.
Osteomyelitis (Campbell)
From adjacent soft tissue infection, open fracture, open treatment of closed fracture, vascular disease, diabetes or immunodeficiency. Hematogenous osteomyelitis is rare in the hand. MRI is suggested for advanced imaging, and CT for sequestra.
Acute or subacute disease without sequestrum may resolve with culture-directed antibiotics after needle aspiration. If no organism is obtained, open drainage and debridement. Chronic infection with sequestra may be salvaged with diaphysectomy, sequestrectomy, external fixation, antibiotic cement and bone grafting, but severe stiffness often limits function, so amputation (at the joint proximal to the involved bone) should be considered, especially in adults.
Osteitis of the distal phalanx from a pulp infection regenerates after drainage, especially in children, and is not sequestrating osteomyelitis.
Bites (Campbell)
Human bites, including clenched-fist injuries, cause some of the most severe infections, most often at the third and fourth MP joints, with chondral or osteochondral fractures in 6%–59%. The mouth carries many species, including E. corrodens. When the fist is extended, the lacerated tendon glides proximally and closes the joint, creating an anaerobic environment. Treat any small laceration over the MP joint as a tooth injury. Obtain radiographs, explore the wound for joint penetration and give antibiotics. Presentation under 24 hours often allows exploration, cultures, antibiotics and close observation. Later presentation may need open joint drainage, irrigation and IV antibiotics. Bite infections presenting more than 8 days after injury carried an 18% chance of amputation in one report. Leave the wound open and give tetanus prophylaxis. Antibiotics are usually continued for 7–10 days. Complications (25%–50%) include osteomyelitis, stiffness, arthritis, amputation and sepsis.
Dog bites: flora include S. aureus, S. viridans, Bacteroides and P. multocida. Debride and irrigate deep wounds and leave them open. Superficial lacerations may be loosely closed after cleansing. Give tetanus prophylaxis with antibiotics.
Cat bites: often puncture wounds that can progress to serious infection (30% of 193 patients were hospitalized, average 3 days). P. multocida is common. Amoxicillin–clavulanate is a common empiric choice, with IV antibiotics for toxicity, rapid progression, deep-space infection or failed oral therapy.
Special hosts and severe infections (Campbell)
IV drug users: more likely to have MRSA. Four types: skin and subcutaneous (I), extensor tendon, periosteum and bone (II), flexor tendon sheath (III, worse prognosis), and arterial injection sequelae with digital necrosis (IV). Treat with hospitalization, aggressive drainage and debridement, lavage, open wounds, splinting, frequent dressing changes and IV antibiotics. Dorsal swelling may be chronic lymphedema rather than infection.
HIV/AIDS: atypical presentation. Herpetic infection can be more virulent and need IV antivirals, and dorsal abscesses may progress to osteomyelitis.
Necrotizing fasciitis: rapidly progressive pain, nonpitting edema, bullae and bluish skin, sometimes with normal temperature and white count. A WBC over 15,400/mm³ with sodium under 135 mmol/L has a reported 90% sensitivity and 99% negative predictive value. CT was reported 100% sensitive and 81% specific. (Campbell)
Complications
Stiffness, tendon adhesions and loss of excursion after tenosynovitis. (Campbell)
Recurrence from inadequate resection or drainage (paronychia, felon). (Campbell)
Osteomyelitis, joint destruction and amputation, particularly in diabetic, immunosuppressed and delayed-presentation patients. (Campbell)
Nerve injury from sharp deep dissection in swollen tissue, and painful scars from poorly placed incisions. (Campbell)
References
Thompson NB. Hand infections. In: Azar FM, Sawyer JR, Throckmorton TW, eds. Campbell's Operative Orthopaedics. 15th ed. Philadelphia: Elsevier; 2026. Chapter 84, Techniques 84.1–84.6.