What should I do about a cat bite on my thumb that's causing limited mobility, redness, and pain?

Seek Medical Evaluation Immediately for Your Cat Bite

You need to see a healthcare provider today or go to an emergency department/urgent care for evaluation and antibiotic treatment. Cat bites to the hand, especially those causing limited mobility and redness, have a high infection rate (approximately 75% contain Pasteurella multocida) and can rapidly progress to serious complications including septic arthritis and tendonitis. 1, 2

Why This Is Urgent

• Cat bites have the highest infection rate of all mammalian bites, with Pasteurella multocida present in 75% of cases and an average of 5 different bacterial species per wound 2
• Hand/thumb bites are particularly dangerous because infection can spread to joints, tendons, and bone within hours 1
• Your symptoms (redness, limited mobility) indicate infection is already developing - this occurred within days of the bite, which is typical for P. multocida infections 2
• Guidelines explicitly state that animal bite wounds contaminated with saliva should be evaluated in a medical facility as soon as possible 1

What the Healthcare Provider Will Do

Wound Assessment and Management

• Thoroughly irrigate and cleanse the wound with sterile saline 1, 2
• Evaluate for deep tissue involvement, including penetration into tendons, joint capsule, or bone (critical for thumb bites) 1
• The wound should NOT be sutured closed if infected 1
• Elevate your hand to reduce swelling 2

Antibiotic Treatment (First-Line)

Amoxicillin-clavulanate 875/125 mg twice daily is the recommended first-line oral antibiotic for cat bites based on its coverage of P. multocida, streptococci, staphylococci, and anaerobes. 1, 2, 3

Alternative oral options if you cannot take amoxicillin-clavulanate:

• Doxycycline 100 mg twice daily (excellent P. multocida coverage, though some streptococci may be resistant) 1, 2, 3
• Penicillin VK plus dicloxacillin (500 mg four times daily each) 1, 2

Antibiotics to AVOID

Do NOT accept prescriptions for these medications as they have poor activity against P. multocida: 2, 3

• First-generation cephalosporins (like cephalexin)
• Macrolides (like erythromycin or azithromycin)
• Clindamycin alone

Additional Care

• Update tetanus vaccination if not current within past 10 years 1, 2
• Follow-up within 24 hours to ensure infection is not progressing 1, 2

Red Flags Requiring Hospitalization

Seek emergency care or hospitalization if you develop: 3

• Fever or systemic symptoms
• Rapidly worsening redness, swelling, or pain despite antibiotics
• Inability to move your thumb at all
• Red streaking up your arm (lymphangitis)
• Pus drainage from the wound

If hospitalized, you would receive IV antibiotics such as ampicillin-sulbactam, piperacillin-tazobactam, or a second-generation cephalosporin. 2, 3

Potential Complications Without Treatment

• Septic arthritis (requires 3-4 weeks of antibiotics) 2
• Osteomyelitis (requires 4-6 weeks of antibiotics) 2
• Tendonitis with permanent loss of thumb function 2
• Systemic infection requiring hospitalization 3

Common Pitfall to Avoid

The most common error is assuming the redness and swelling are just "inflammation" rather than infection. While inflammation causes redness and swelling, cat bite wounds contain bacteria that cause true infection requiring antibiotics - not just anti-inflammatory treatment. 4 The limited mobility of your thumb suggests the infection may already involve deeper structures. 1