Rat bite injection

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rat bite wound management rabies prophylaxis tetanus injection protocol 2024

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Rat Bite - Management & Injections

1. Immediate Wound Care

Wash the wound thoroughly with soap and water for 10-15 minutes - this is the single most important step
Irrigate with normal saline or dilute povidone-iodine solution
Debride devitalized tissue if present
Wound is generally left open (not sutured primarily) due to infection risk
Apply antiseptic dressing

2. Injections to Give

A. Tetanus Prophylaxis

Vaccination history	Action
Unknown / < 3 doses ever	Tetanus toxoid (TT/Td) + Tetanus Immunoglobulin (TIG 250 IU IM)
3+ doses, last dose < 5 years ago	Nothing needed
3+ doses, last dose 5-10 years ago	TT/Td booster (0.5 mL IM)
3+ doses, last dose > 10 years ago	TT/Td booster (0.5 mL IM)

B. Rabies Post-Exposure Prophylaxis (PEP)

Rodents (rats, mice, squirrels) are generally considered LOW risk for rabies by the CDC. In most developed countries, rabies PEP is NOT routinely recommended for rat bites.

However, assess based on:

Geographic region (enzootic rabies in wild rodents in some areas)
Animal behavior (unprovoked bite, sick-appearing animal)
Local public health guidance

If PEP is indicated (per local guidelines or wild rat in enzootic area):

Immunization status	Schedule
Never vaccinated	HRIG (20 IU/kg) infiltrated at wound site on Day 0 + Rabies vaccine 1 mL IM (deltoid) on Days 0, 3, 7, 14
Previously vaccinated	Rabies vaccine only on Days 0 and 3 (NO immunoglobulin)

HRIG and rabies vaccine must NOT be given in the same syringe or same anatomical site.

C. Antibiotics - For Rat Bite Fever Prevention

According to Rosen's Emergency Medicine, antibiotic prophylaxis after a rat bite is NOT routinely recommended because the risk of infection after a bite is low.

If the patient develops illness (fever, rash, arthralgia within 3 days-3 weeks post bite), treat for Rat-Bite Fever:

Organism	First-line	Penicillin allergy
Streptobacillus moniliformis (worldwide)	Penicillin G IV 7-10 days (or Amoxicillin-clavulanate orally)	Doxycycline or clindamycin
Spirillum minus (Asia - "Sodoku")	Penicillin G IV 7-10 days	Doxycycline
Endocarditis (complication)	High-dose Penicillin G IV x 4 weeks (+/- streptomycin/gentamicin)	-

3. Rat-Bite Fever - What to Watch For

Two clinical syndromes to recognize post-bite:

Streptobacillary fever (S. moniliformis - more common, worldwide):

Incubation: 3 days to 3 weeks (usually < 7 days)
Classic triad: Fever + migratory polyarthritis + rash
Rash: maculopapular/petechial on palms, soles, and around joints (appears 2-3 days after fever)
Note: the bite wound usually heals normally - no local inflammation
Untreated mortality: 7-13%
Complications: endocarditis, brain abscesses, septic arthritis, meningitis

Spirillary fever / Sodoku (S. minus - Asia primarily):

Incubation: 7-21 days
Bite site re-ulcerates; fever + lymphadenopathy + red/purple plaques
Arthritis is rare

4. Disposition

Most rat bites can be discharged home with wound care instructions
Return precautions: fever, chills, rash, joint pain within 1-3 weeks
Follow-up: in 48 hours to check wound

Summary Injection Card

Injection	Dose & Route	When
Tetanus toxoid (TT/Td)	0.5 mL IM (deltoid)	If not up to date
TIG (human)	250 IU IM (different site from TT)	If unvaccinated
HRIG	20 IU/kg at wound site	Only if rabies PEP indicated
Rabies vaccine	1 mL IM (deltoid) Days 0,3,7,14	Only if rabies PEP indicated
Antibiotics	Not routinely needed	Give only if rat-bite fever develops

Sources:

Rosen's Emergency Medicine, block 8 - Rodent bites management
Red Book 2021 (AAP), p. 974-975 - Rat-bite fever treatment
Fitzpatrick's Dermatology, block 24 - Rat-bite fever clinical features
CDC Rabies PEP guidelines
WHO Rabies PEP Protocol

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