What antibiotics are recommended for a cat scratch with signs of infection?

Antibiotic Treatment for Cat Scratch Infections

For cat scratches showing signs of infection, amoxicillin/clavulanate (500/875 mg twice daily) is the recommended first-line antibiotic treatment. 1

Treatment Algorithm for Cat Scratch Infections

For Standard Cat Scratch Infections:

• Amoxicillin/clavulanate (500/875 mg twice daily orally) is the first-line treatment for infected cat scratches, providing coverage against common pathogens including Pasteurella multocida 1
• For penicillin-allergic patients, doxycycline (100 mg twice daily) is an excellent alternative with good activity against Pasteurella multocida 1
• For more severe infections requiring intravenous therapy, ampicillin-sulbactam (1.5-3.0 g every 6-8 hours) is recommended 1

For Cat Scratch Disease (Bartonella henselae infection):

• Azithromycin is the first-line treatment (500 mg on day 1, followed by 250 mg for 4 additional days) for confirmed cat scratch disease 2
• Alternative treatments include:
  • Doxycycline (100 mg twice daily) 2
  • Erythromycin (500 mg four times daily) 2
  • Ciprofloxacin (500-750 mg twice daily) has shown efficacy in some cases 3

Clinical Presentation and Diagnosis

• Typical cat scratch infections present with local inflammation, redness, and pain at the scratch site 1
• Cat scratch disease specifically presents with a papule or pustule 3-30 days after a scratch, followed by regional lymphadenopathy about 3 weeks later 1, 2
• Lymphadenopathy in cat scratch disease typically resolves within 1-6 months, with node suppuration occurring in approximately 10% of cases 2
• Extranodal disease (affecting CNS, liver, spleen, bone, or lung) develops in about 2% of cat scratch disease cases 2

Treatment Duration and Special Considerations

• For simple infected cat scratches, 7-10 days of antibiotic therapy is typically sufficient 1
• For confirmed cat scratch disease, 5 days of azithromycin or 7-10 days of alternative antibiotics is recommended 2, 4
• More aggressive and prolonged treatment is needed for immunocompromised patients, particularly those with HIV who develop bacillary angiomatosis 2

Important Caveats and Pitfalls

• Cat scratch disease is often self-limiting in immunocompetent hosts and may not require antibiotic treatment for mild cases 5, 4
• Fluoroquinolones (like ciprofloxacin) are contraindicated in children and adolescents under 18 years of age 1
• Tetracyclines (like doxycycline) should be avoided in children under 8 years of age and pregnant women 1, 2
• For pregnant women requiring treatment, erythromycin is the preferred option 2
• Failure to recognize disseminated forms of cat scratch disease can lead to delayed treatment of potentially serious complications 4

Prevention Measures

• Prompt cleaning of cat scratches with soap and water can help prevent infection 2
• Avoid rough play with cats that might lead to scratches 2
• Comprehensive flea control for cats helps prevent Bartonella transmission 2
• Do not allow cats to lick open wounds 2