I have a red, painful right thumb that appears to be a bite or bruise; how should I manage it?

Management of Red, Painful Right Thumb with Suspected Bite or Bruise

Immediately irrigate the wound with copious amounts of running tap water or sterile saline until all visible debris is removed, apply direct pressure if bleeding, cover with a clean occlusive dressing, and start oral amoxicillin-clavulanate prophylaxis if this is a bite wound—especially given the high-risk location on the hand. 1, 2

Immediate Wound Care

Hemorrhage Control (if bleeding)

• Apply direct pressure immediately using gauze or a clean cloth; this is the most effective initial intervention for bleeding control 3, 4
• Continue pressure for several minutes until bleeding stops 4
• Elevate the hand above heart level to reduce blood flow and swelling 1, 2

Wound Irrigation and Cleaning

• Irrigate thoroughly with large volumes of running tap water or sterile saline until no visible debris remains 3, 1, 2
• Running tap water is as effective as sterile saline and superior to antiseptic solutions like povidone-iodine for irrigation 1, 5
• Do not use antiseptic solutions (iodine, hydrogen peroxide) for irrigation—they provide no advantage over water/saline and may damage healing tissue 1, 6, 7
• Avoid aggressive scrubbing that causes additional tissue damage 1

Wound Coverage

• After cleaning, cover the wound with antibiotic ointment (such as Polysporin or bacitracin) and a clean occlusive dressing to promote healing and prevent infection 3, 2, 6
• Apply antibiotic ointment only if you have no known allergies to the antibiotic 3
• Keep the wound covered to maintain a moist environment, which accelerates healing 2, 6

Antibiotic Prophylaxis (Critical for Bite Wounds)

If This Is a Bite Wound

Hand wounds from bites always require prophylactic antibiotics due to the highest infection risk of any anatomic location 1

• First-line treatment: Amoxicillin-clavulanate for both prophylaxis and treatment 1
• This covers the polymicrobial flora typical of animal and human bites, including Pasteurella multocida (present in 50-75% of cat/dog bites) 1

Alternative Antibiotics (if penicillin-allergic)

• Doxycycline monotherapy 1
• Fluoroquinolone (ciprofloxacin, levofloxacin, or moxifloxacin) plus metronidazole or clindamycin 1

Antibiotics to Avoid

Do not use first-generation cephalosporins (cephalexin), macrolides, or clindamycin alone—these have poor coverage against Pasteurella species 1

Tetanus Prophylaxis

• Administer 0.5 mL tetanus toxoid intramuscularly if your vaccination status is outdated or unknown 1, 2, 8
• Give a booster if >10 years since last dose for clean wounds 8
• Give a booster if >5 years since last dose for contaminated/puncture wounds 8
• The deltoid muscle is the preferred injection site 8

When to Seek Immediate Medical Attention

Urgent Evaluation Required If:

• Any bite wound to the hand—these require evaluation by a hand surgery specialist due to high risk of joint penetration, septic arthritis, and osteomyelitis 1
• Wound is deep, gaping, or involves tendons, joints, or bone 5
• Unable to move the thumb normally 1
• Numbness or tingling in the thumb 1
• The thumb appears blue or extremely pale (vascular compromise) 3
• Signs of infection develop (see below) 1, 2

Signs of Infection Requiring Re-evaluation:

• Progressive redness spreading beyond the wound 2
• Increasing pain disproportionate to the injury 1, 2
• Warmth, swelling, or tenderness that worsens 2
• Purulent (pus) or foul-smelling drainage 2
• Red streaks extending up the arm (lymphangitis) 2
• Fever or chills 2

Follow-Up Care

• Arrange follow-up within 24 hours (phone or office visit) to monitor for complications 1, 2
• Keep the hand elevated as much as possible for the first 48-72 hours 1, 2
• Change dressings daily or when soiled, using clean technique 2
• Continue antibiotic ointment application with each dressing change 2, 6

Critical Pitfalls to Avoid

• Do not close the wound with sutures or tape if it is a bite wound or presents >8 hours after injury—these should heal by secondary intention 1
• Do not delay medical evaluation if this is a bite to the hand—infection rates are 10-50% depending on bite type 1
• Do not use inadequate antibiotic coverage for suspected bites (avoid cephalexin, macrolides, clindamycin alone) 1
• Do not apply antiseptics to open wounds—use only for intact skin preparation 6, 7
• Do not ignore worsening pain—this may indicate deep infection, abscess, or bone/joint involvement 1, 2