From the Guidelines
For a dog scratch, antibiotics are generally not needed unless the wound is deep, shows signs of infection, or the person has a compromised immune system. If antibiotics are required, common first-line options include amoxicillin-clavulanate (Augmentin) 875/125 mg twice daily for 5-7 days, as recommended by the Infectious Diseases Society of America in their 2014 guidelines 1. Before considering antibiotics, it is essential to:
- Clean the wound thoroughly with soap and water
- Apply an antiseptic like hydrogen peroxide or povidone-iodine
- Cover with a clean bandage Watch for signs of infection such as:
- Increasing redness
- Swelling
- Warmth
- Pus
- Red streaks extending from the wound These symptoms warrant medical attention. Antibiotics are prescribed selectively because most dog scratches heal well with proper wound care alone, and unnecessary antibiotic use contributes to antibiotic resistance, as noted in the guidelines 1. Additionally, ensure your tetanus vaccination is up to date, as any break in the skin can pose a tetanus risk. It's also important to note that the choice of antibiotic should be based on the severity of the infection and the potential causative pathogens, with considerations for coverage against Pasteurella multocida, a common pathogen in animal bites, as discussed in the guidelines 1.
From the Research
Antibiotic Treatment for Dog Scratches
- The bacterium Capnocytophaga canimorsus, commonly found in the oral flora of dogs and cats, can be transmitted to humans through bites, scratches, or licks, and may cause severe infections 2.
- In immunocompetent individuals, Capnocytophaga canimorsus infections can lead to sepsis, with a case-fatality rate of 29.7%, and early wound cleansing, initial penicillin therapy with beta-lactamase inhibitors, and surgical removal of infectious focus may be protective factors 3.
- A study of Capnocytophaga spp. infections in California found that 85% of identified species were Capnocytophaga canimorsus, and most patients presented with sepsis, often without a documented animal bite 4.
- For the treatment of moderate-grade dog bite wounds, amoxicillin-clavulanic acid has been shown to be an effective empirical antimicrobial choice, with over 90% of gram-negative and gram-positive isolates susceptible to this antibiotic 5.
- The antimicrobial treatment of Capnocytophaga infections often involves the use of beta-lactamase inhibitor combinations, such as imipenem/cilastatin or clindamycin, which have been shown to be effective against these bacteria 6.
Recommended Antibiotics
- Amoxicillin-clavulanic acid
- Imipenem/cilastatin
- Clindamycin
- Beta-lactamase inhibitor combinations
Important Considerations
- Early wound cleansing and surgical removal of infectious focus may be important for preventing severe outcomes 3, 4.
- The use of empirical antibiotics, such as amoxicillin-clavulanic acid, should be guided by antimicrobial stewardship principles to minimize the risk of resistance 5.
- The choice of antibiotic should be based on the suspected or confirmed causative organism and its antimicrobial susceptibility pattern 6.