Bites & Envenomation Quick Guide

Clinical reference for domestic and wild exposures (USA / North Carolina focus). Tap any blue bar to expand details. No JavaScript required.

Section A — Quick Reference

Category	Common Example	Scientific Name	Key Risks	Details
Domestic (Mammal)	Cat	Felis catus	Deep punctures; Pasteurella multocida	View Treatment Copious irrigation; gentle debridement. Prophylaxis: amoxicillin–clavulanate 875/125 mg PO BID × 5–7 days. Beta-lactam allergy: see “Antibiotic Alternatives” below. Tetanus booster if >5 years; rabies PEP if cat unavailable for observation/testing.
Domestic (Mammal)	Dog	Canis lupus familiaris	Crush/tear injuries; mixed flora	View Treatment Irrigation; debride devitalized tissue; explore for tendon/joint violation. Amoxicillin–clavulanate first-line; consider broader coverage for hand wounds, deep punctures, or immunocompromise. Tetanus update; rabies risk assessment. Primary closure often acceptable except high-risk locations (e.g., hand).
Human	Closed-fist injury (“fight bite”)	Homo sapiens	Eikenella corrodens; joint inoculation risk	View Treatment Avoid primary closure on the hand; evaluate for tendon, joint, bone involvement; consider imaging. Oral: amoxicillin–clavulanate. IV: ampicillin–sulbactam if needed. Beta-lactam allergy: see “Antibiotic Alternatives.” Tetanus update; assess blood-borne pathogen exposure as indicated.
Arthropod (Tick)	Blacklegged tick	Ixodes scapularis	Lyme, babesiosis, anaplasmosis	View Treatment Remove with fine-tipped tweezers at skin line; steady upward traction. Lyme prophylaxis: doxycycline 200 mg PO once within 72 h if high-risk criteria met (engorged Ixodes, attachment ~≥36 h, local risk supports PEP). Observe for rash/systemic symptoms for 30 days.
Arthropod (Spider)	Black widow	Latrodectus mactans	Neurotoxin; pain, spasm	View Treatment Supportive care; opioids for pain; benzodiazepines for spasm. Antivenom for severe/refractory cases after risk-benefit discussion.
Arthropod (Spider)	Brown recluse	Loxosceles reclusa	Local necrosis; systemic loxoscelism uncommon	View Treatment Local care, analgesia; avoid early wide excision. Delayed debridement if needed; evaluate for hemolysis if systemic signs.
Reptile (Snake)	Copperhead	Agkistrodon contortrix	Common NC envenomation; local pain/swelling	View Treatment Immobilize limb; remove constrictive items; keep at heart level. Hospital eval; antivenom if progressive swelling, systemic toxicity, or coagulopathy. Avoid incision, suction, ice, tourniquets.

Section B — Expanded Species List (USA / North Carolina Focus)

Common Name	Scientific Name	Risk Notes	Details
Raccoon	Procyon lotor	Rabies reservoir in NC	View Treatment Immediate soap/water wash; irrigate thoroughly. Rabies PEP unless the animal tests negative via public health. Tetanus booster as indicated.
Bat (various)	Chiroptera	Rabies risk; wounds may be occult	View Treatment Rabies PEP if bat not available for testing or exposure cannot be ruled out (asleep in room with bat, child, intoxicated, cognitively impaired). Tetanus update.
Cottonmouth (Water Moccasin)	Agkistrodon piscivorus	Hemotoxic venom; tissue injury	View Treatment Immobilize; prompt hospital care; serial limb measurements. Antivenom if progression/systemic effects. Labs: CBC, BMP, PT/INR, fibrinogen, CK.
Eastern Diamondback Rattlesnake	Crotalus adamanteus	Severe envenomation; coagulopathy risk	View Treatment Immobilize limb; rapid transport; avoid harmful field techniques. Antivenom per protocol; monitor for recurrent coagulopathy.
Timber Rattlesnake	Crotalus horridus	Hemotoxic ± neurotoxic effects	View Treatment Hospital observation; antivenom guided by progression. Continuous cardiopulmonary and coagulation monitoring.
Eastern Coral Snake (regional)	Micrurus fulvius	Neurotoxic; cranial nerve/respiratory risk	View Treatment Rapid evaluation; observe for delayed neurotoxicity. Antivenom if available/indicated; airway support as needed.
American Dog Tick	Dermacentor variabilis	RMSF vector in NC	View Treatment Prompt tick removal; do not crush body. Empiric doxycycline for suspected RMSF regardless of age when clinically indicated.
Black Widow	Latrodectus mactans	Pain, spasm, autonomic symptoms	View Treatment Analgesia and benzodiazepines; consider antivenom for severe cases with shared decision making.
Brown Recluse	Loxosceles reclusa	Necrotic ulcers possible; true bites uncommon in NC	View Treatment Local care, tetanus as indicated, delayed debridement if necessary. Assess for hemolysis/systemic symptoms if suspected.

Antibiotic Alternatives for Penicillin Allergy

Show Allergy-Safe Regimens for Mammalian Bites

Goal coverage: Pasteurella spp., streptococci, staphylococci (consider community MRSA), and oral anaerobes. Tailor to severity, site, comorbidities, and local stewardship.

• Adults (oral):
  • Doxycycline + metronidazole
  • Clindamycin + ciprofloxacin or clindamycin + levofloxacin
  • Moxifloxacin monotherapy (adults only; check QT/pregnancy)
  • Trimethoprim–sulfamethoxazole + metronidazole
• Adults (IV):
  • Clindamycin + a fluoroquinolone for severe beta-lactam allergy
  • Doxycycline + metronidazole if appropriate/available IV
  • Non-anaphylactic PCN reactions: consider ceftriaxone + metronidazole per allergy history/stewardship
• Pediatrics: discuss with pediatrics/ID for age-specific dosing; options may include TMP-SMX + clindamycin or TMP-SMX + metronidazole tailored to Pasteurella, streptococci, and anaerobes.
• Human bites (hand/closed-fist): adult options include clindamycin + ciprofloxacin, clindamycin + levofloxacin, or doxycycline + metronidazole; ensure early surgical eval for suspected joint/tendon sheath violation.
• Duration: typically 3–5 days for prophylaxis of high-risk wounds; 5–7+ days for infection, extended per clinical course.

Notes: Avoid fluoroquinolones in pregnancy when possible; moxifloxacin not for children. Doxycycline generally avoided in pregnancy (short courses for certain tick-borne illnesses are exceptions). Adjust for renal function/drug interactions.

North Carolina Rabies PEP Quick Flow

Show PEP Decision Steps & Dosing

1. Immediate wound care: Wash with soap/water; irrigate copiously.
2. Animal type & availability:
   • Dog/cat/ferret healthy & available: 10-day observation; PEP only if animal becomes ill or cannot be observed.
   • Wild carnivores (raccoon, fox, skunk) or bats: if exposure possible and animal not promptly testable, begin PEP; coordinate with public health.
   • Others (livestock, small rodents, lagomorphs): consult public health.
3. Exposure scenarios: Bite or saliva to mucosa/broken skin = exposure. Bat encounters where a bite can’t be ruled out = treat as exposure.
4. PEP (not previously vaccinated):
   • Vaccine IM on days 0, 3, 7, 14 (deltoid adults; anterolateral thigh young children).
   • HRIG 20 IU/kg once on day 0: infiltrate into/around wounds; remainder IM at a site distant from vaccine.
   • Immunocompromised: add day-28 vaccine dose; verify response per public health.
5. PEP (previously vaccinated or pre-exposed): vaccine IM on days 0 and 3; no HRIG.
6. Coordination: contact your local NC health department for testing/exposure classification and schedule support.

Administration tips: Separate syringes/sites for vaccine and HRIG; don’t mix; avoid gluteal vaccine administration.

Abbreviation Key

Show Medical Abbreviation Key

• PEP: Post-exposure prophylaxis
• PO: By mouth
• IV: Intravenous
• IM: Intramuscular
• BID: Twice daily
• TID: Three times daily
• q (e.g., q8h): Every (every 8 hours)
• RMSF: Rocky Mountain spotted fever
• CK: Creatine kinase
• NC: North Carolina

Always follow local public health guidance. Adjust choices for renal function, pregnancy, pediatrics, allergies, and antimicrobial stewardship.