What is the optimal prophylactic antibiotic and additional management for a patient with a 2 cm scalp laceration that will be primarily closed and a 0.4 cm hand puncture wound left open after a bite from a known, vaccinated dog?

Optimal Management of Dog Bite Wounds to Scalp and Hand

Antibiotic Selection

Amoxicillin-clavulanate 875/125 mg twice daily for 3-5 days is the first-line antibiotic for these dog bite wounds, providing essential coverage against Pasteurella multocida, Staphylococcus aureus, Streptococcus species, and anaerobes commonly found in dog bites. 1, 2

• This recommendation is based on IDSA guidelines that specifically identify amoxicillin-clavulanate as the preferred oral agent for animal bite wounds 1
• Your patient meets multiple criteria for preemptive antibiotic therapy: moderate severity injury, hand involvement (high-risk location), and facial/scalp wound requiring closure 1
• Studies of facial dog bites treated with amoxicillin-clavulanic acid showed zero wound infections when used prophylactically 3

Alternative for Penicillin Allergy

• Doxycycline 100 mg twice daily is the recommended alternative, with excellent activity against Pasteurella multocida 1, 2
• Avoid first-generation cephalosporins, macrolides, or clindamycin alone—these have poor activity against Pasteurella multocida and are explicitly inadequate for dog bites 2

Wound Management Approach

Scalp Laceration (2 cm with flap)

Primary closure of the scalp wound after copious irrigation and cautious debridement is appropriate and recommended. 1, 2

• Facial and scalp wounds are the explicit exception to the "do not close bite wounds" rule due to rich vascular supply and cosmetic importance 1, 2
• Use copious irrigation with sterile normal saline using a 20-mL or larger syringe before closure 2, 4
• Perform cautious debridement of devitalized tissue only, preserving as much viable tissue as possible 2
• Your plan for 4 sutures with wide spacing is reasonable for this location 1

Hand Puncture Wound (0.4 cm)

Leaving the hand puncture wound open is the correct decision—hand wounds have significantly higher infection rates when closed. 1

• Multiple studies demonstrate that closing hand bite wounds is associated with higher infection rates than other locations 1, 5
• Puncture wounds specifically should not be closed, even when excised wounds elsewhere might be 1
• The hand wound still requires thorough irrigation with normal saline using a 20-mL or larger syringe 4
• Explore the wound for potential tendon, joint capsule, or periosteum penetration, as these require extended antibiotic therapy (2-4 weeks) 1, 4

Essential Additional Measures

Tetanus Prophylaxis

Administer tetanus toxoid if the patient's last vaccination was more than 5 years ago for this contaminated wound. 1, 2

• Tdap is preferred over Td if the patient has not previously received Tdap 1
• For clean wounds, the threshold is 10 years, but dog bites are considered "dirty wounds" requiring the 5-year threshold 1
• If the patient has not completed the primary vaccine series, they should complete it 1

Rabies Assessment

Consultation with local health officials is mandatory to determine if rabies post-exposure prophylaxis is indicated, even though the dog is known and vaccinated. 1, 2, 4

• This is a legal and medical requirement for all dog bites 4
• Documentation of the dog's vaccination status should be obtained 4
• If rabies prophylaxis is indicated, it includes both immune globulin and vaccine on days 0,3,7, and 14 4

Wound Care Instructions

• Elevate both the hand and head when possible to reduce swelling 2
• Schedule close follow-up within 24-48 hours to monitor for signs of infection 2
• Instruct the patient to watch for increasing pain, redness, swelling, or purulent discharge 2

Critical Pitfalls to Avoid

• Do not close the hand puncture wound—this significantly increases infection risk in this high-risk location 1, 5
• Do not use inadequate irrigation—this is the most important factor in preventing infection and requires vigorous flushing with at least 20 mL syringe 2, 4
• Do not prescribe cephalexin, clindamycin, or macrolides alone—these miss Pasteurella multocida coverage 2, 6
• Do not skip rabies assessment—even known, vaccinated dogs require evaluation per local health department protocols 1, 4
• Do not forget to assess for deeper structure involvement in the hand wound—penetration of joint capsule or periosteum changes management to 2-4 weeks of antibiotics 1