Bites and stings

🩺 Bites and stings are a common reason for presentation to primary care, urgent care, and emergency departments in the UK. While many are self-limiting, some carry risks of serious infection, anaphylaxis, or zoonotic disease. ⚖️ NICE CKS guidance provides a framework for safe, evidence-based management in both adults and children.

💡 Key principle: Always assess for systemic involvement (airway compromise, widespread allergic reaction, sepsis) and local complications (infection, deep tissue injury, tissue necrosis).

🧪 General Approach

• 🔎 History: Type of bite/sting, time of onset, environment (UK vs abroad), systemic symptoms (fever, rash, SOB, collapse).
• 👀 Examination: Local wound (size, depth, discharge, foreign body), lymphadenopathy, systemic features.
• 🧾 Investigations (if severe/systemic): FBC, CRP, blood cultures, wound swab, U&E/LFTs if septic, Lyme serology (if tick + systemic).
• 💉 Immediate priorities: ABCDE approach, airway protection in suspected anaphylaxis, haemostasis, pain relief.
• 💊 Prophylaxis checks: Tetanus, rabies (if from endemic regions), hepatitis B (human bites).

🦟 Bites and Stings – Clinical Presentation & Management

• 🐝 Insect Bites/Stings (bees, wasps, mosquitoes)
  • Clinical: Local itching, erythema, swelling; may cause anaphylaxis 🚨.
  • Management:
    • Mild ➝ ❄️ cold compress, non-sedating antihistamines, topical steroids
    • Secondary infection ➝ oral antibiotics (flucloxacillin/clarithromycin)
    • Anaphylaxis ➝ 🚑 IM adrenaline 500 mcg (adult) / 150–300 mcg (child) + O2, IV fluids, antihistamines, steroids
    • Prevention ➝ repellents, protective clothing, avoidance advice
• 🕷️ Tick Bites
  • Clinical: Local redness; risk of Lyme disease ➝ erythema migrans (target rash), flu-like illness, neurological/arthritic features later.
  • Management:
    • Careful removal with fine tweezers (close to skin, steady pull)
    • Do not burn/suffocate the tick ❌
    • If erythema migrans ➝ treat empirically (doxycycline 100 mg BD 21 days; amoxicillin in pregnancy/children)
• 🧑 Human Bites
  • Clinical: Puncture/tearing wounds; high risk of infection (Eikenella, anaerobes).
  • Management:
    • Immediate irrigation, wound exploration, remove debris
    • Prophylactic antibiotics ➝ co-amoxiclav 7 days
    • Consider HIV/hepatitis B exposure prophylaxis if high-risk
    • Tetanus vaccination if needed
    • Escalate to IV antibiotics if cellulitis/sepsis
• 🐶 Animal Bites (dog, cat)
  • Clinical: Dogs cause crush injuries; cats cause deep puncture wounds (→ Pasteurella multocida risk).
  • Management:
    • Thorough cleaning ± surgical debridement
    • Antibiotics ➝ co-amoxiclav 7 days
    • Tetanus update
    • Rabies prophylaxis if animal from high-risk area 🌍
• 🕸️ Spider Bites
  • Clinical: Local pain, erythema, swelling. Rare systemic ➝ cramps, abdominal pain.
  • Management:
    • Mild ➝ cold compress, analgesia
    • Severe/systemic ➝ admit, supportive care ± antivenom
• 🌊 Jellyfish Stings
  • Clinical: Burning pain, linear welts. Rare systemic ➝ arrhythmias, respiratory compromise.
  • Management:
    • Rinse with seawater (❌ not fresh water)
    • Hot water immersion (40–45°C, 20–30 mins) to inactivate venom
    • Systemic involvement ➝ emergency care

Special Considerations

• 👶 Children: More prone to systemic reactions and severe swelling. Always use weight-based dosing for antihistamines/antibiotics.
• 🤰 Pregnancy: Avoid doxycycline (tick bites) – use amoxicillin. Always consider maternal-fetal safety.
• 🧓 Immunocompromised: Higher risk of infection and poor healing ➝ lower threshold for IV antibiotics & admission.
• 🌍 Travel-related: Consider exotic infections (rabies, leishmaniasis, malaria, dengue). Always take a travel history.

Red Flags 🚩

• Rapidly spreading erythema, cellulitis, systemic upset → sepsis pathway.
• Signs of anaphylaxis (airway obstruction, wheeze, hypotension, collapse).
• Bites near critical structures (face, hands, genitals, joints) → higher complication risk.
• Deep puncture wounds (cats, humans) → very high infection risk.

Summary

🌟 Clinical takeaway: Most insect bites are benign, but human and cat bites, tick bites, and systemic allergic reactions require urgent recognition and early treatment. Always check tetanus & rabies status, and never miss anaphylaxis 🚨.

References

• NICE CKS: Insect bites & stings
• NICE CKS: Human bites
• NICE CKS: Animal bites
• UKHSA: Lyme disease guidance

🧾 Clinical Case Examples

Case 1 – Wasp sting anaphylaxis 🚑
A 40-year-old man is stung on the arm while gardening. Within 10 minutes he develops urticaria, lip swelling, stridor, and hypotension. 👉 Diagnosis: Anaphylaxis secondary to wasp sting. 👉 Management: IM adrenaline 500 mcg (1:1000), oxygen, IV fluids, admit for observation. Prescribe adrenaline auto-injector on discharge.

Case 2 – Infected cat bite 🐱
A 65-year-old woman presents 24 h after a cat bite to her hand. It is swollen, erythematous, and very tender. She is febrile (38.5 °C). 👉 Diagnosis: Cellulitis from Pasteurella multocida. 👉 Management: Wound cleaning, co-amoxiclav 7 days, IV antibiotics if deteriorating. Check tetanus status.

Case 3 – Tick bite with erythema migrans 🕷️
A 12-year-old boy returns from a camping trip in the New Forest. Ten days later he develops a circular expanding red rash with central clearing on his thigh, plus malaise. 👉 Diagnosis: Lyme disease (early). 👉 Management: Doxycycline 21 days (or amoxicillin if <12 y or pregnant).

Case 4 – Human bite in A&E 👊
A 19-year-old man is punched in the mouth during a fight, sustaining a “clenched fist” injury over the 3rd MCP joint. The wound is punctured and swollen. 👉 Diagnosis: Human bite with high infection risk (Eikenella, anaerobes). 👉 Management: Urgent wound irrigation, exploration, co-amoxiclav 7 days, hand surgery referral if joint involved.

Case 5 – Jellyfish sting abroad 🌊
A 25-year-old holidaymaker in Australia presents with burning pain and linear red welts after swimming. He is in distress but haemodynamically stable. 👉 Diagnosis: Jellyfish sting. 👉 Management: Rinse with seawater, hot water immersion 40–45 °C for 20 min, analgesia. Admit if systemic features (arrhythmia, respiratory compromise).