Insect bites, stings and scorpions
Big itchy swelling within a day is a reaction, not infection. Watch for anaphylaxis, treat scorpion stings in children seriously, and think Congo fever after tick bites.
A 7-year-old from a village in Sindh was stung by a scorpion on the foot 2 hours ago while sleeping on the floor. He is sweating, vomiting and salivating, with cold hands. BP 150/100, pulse 140, RR 34, crackles at both bases.
A day later, a butcher is brought in after Eid with fever, muscle pain, bleeding gums and platelets 30,000/µL.
How dangerous is the sting, what do you give, and what does the butcher need?
- Anaphylaxis after a stingIM adrenaline now. See the anaphylaxis guide.
- Scorpion sting with sweating, vomiting, high BP, cold handsSevere envenoming: admit, prazosin, HDU if pulmonary oedema.
- Fever and bleeding after a tick bite or animal blood contactCrimean-Congo haemorrhagic fever: isolate, protect staff, notify.
- Local reaction onlyCold compress, oral antihistamine, analgesia.
- Large local swellingAntihistamine, antibiotics only if infected.
- Infected biteSpreading redness, pus, fever: flucloxacillin.
- Bee stingScrape the sting out quickly.
- TetanusCheck status.
- Any anaphylaxis
- Scorpion sting in a child with systemic features
- Pulmonary oedema, very high BP or shock after a sting
- Fever and bleeding after a tick bite or animal slaughter
- Multiple stings (wasps, bees)
- Anaphylaxis
- Scorpion myocarditis and pulmonary oedema
- Crimean-Congo haemorrhagic fever
- Snake bite mistaken for an insect bite
- Cellulitis
- Tick-borne infection
| Local scorpion pain | Ice, oral analgesia, local anaesthetic infiltration around the sting |
| Prazosin (scorpion) | Adult 1 mg orally, child 30 micrograms/kg, repeat every 3–6 hours per response |
| Scorpion observation | Children at least 6 hours, adults 4–6 hours |
| Anaphylaxis | IM adrenaline 0.5 mg (adult), 0.3 mg (6–12 years), 0.15 mg (under 6) |
| Antibiotics | Only if infected, not for swelling alone |
| CCHF | Fever with bleeding 1–9 days after tick bite or contact with animal blood |
Check every dose against a current drug reference and your hospital protocol.
On this page
Local reactions
- Redness, swelling, itch and pain at the site are expected.
- Large local reactions (swelling over 10 cm, peaking at 48 hours) are allergic, not infection. Antihistamine, cold compress, elevation; a short oral steroid only if very large.
- Antibiotics only if there are signs of infection: spreading redness after 48 hours, pus, fever, lymphangitis.
Anaphylaxis
Any sting followed by breathing difficulty, wheeze, throat tightness, swelling of the face or tongue, low BP or collapse: IM adrenaline immediately. See anaphylaxis. Patients with previous systemic reactions should carry adrenaline and be referred to an allergy service where available.
Scorpion stings in Pakistan
Scorpion stings are common in rural Sindh, Punjab and Balochistan, especially in summer and at night. Children are at greatest risk. The venom causes an autonomic storm: catecholamine release leading to high BP, pulmonary oedema and myocarditis.
- Ice, analgesia, local anaesthetic
- Observe 4–6 hours (children longer)
- Autonomic storm
- Prazosin, admit
- HDU or ICU
- Prazosin, oxygen, CPAP
- Avoid large fluid boluses
- Prazosin blocks the catecholamine effects and has reduced deaths. Watch for low BP after the first dose (lie the patient down).
- Scorpion antivenom is used in some centres; follow local availability and guidance.
- Avoid atropine (worsens tachycardia) and avoid large fluid boluses in pulmonary oedema.
Crimean-Congo haemorrhagic fever (CCHF)
- Spread by Hyalomma tick bites and contact with animal blood, especially around Eid ul Adha and in livestock workers, butchers and healthcare workers.
- Incubation 1–9 days. Sudden fever, muscle pain, headache, then bleeding (gums, nose, gut, skin), low platelets, high ALT.
- Isolate with full barrier precautions. Protect staff (gloves, gown, mask, eye protection). Notify public health.
- Supportive care, platelets and blood as needed; ribavirin per national guidance.
Treatment
Prevention
- Shake out shoes and bedding; avoid sleeping on the floor; use a bed net.
- Wear gloves when moving firewood, stones or hay.
- Use tick repellents and protective clothing around livestock; wear gloves when slaughtering.
Common mistakes
- Giving antibiotics for every swollen bite.
- Sending a child home too soon after a scorpion sting.
- Giving large fluid boluses to a child with scorpion pulmonary oedema.
- Missing CCHF in a febrile, bleeding butcher after Eid.
- Treating anaphylaxis with antihistamines and steroids only.
Frequently asked questions
Do insect bites need antibiotics?
No, unless infected (spreading redness after 48 hours, pus, fever). Swelling and itching are allergic, not infection.
What is the treatment of a scorpion sting?
Pain relief and observation for local stings. Systemic features (sweating, vomiting, high BP, cold hands) need prazosin and admission; pulmonary oedema needs HDU care.
What is Crimean-Congo haemorrhagic fever?
A viral infection spread by ticks and contact with animal blood, causing fever, bleeding and low platelets. Patients must be isolated with full precautions.
What should be done for a bee sting?
Scrape out the sting quickly, cold compress, antihistamine for itch, and IM adrenaline if there are signs of anaphylaxis.
Test yourself
Exam-style questions on this guide, from our two question banks. Choose an answer to see why each option is right or wrong.
1. A child stung by a scorpion has sweating, vomiting, cold hands and BP 150/100. Which drug is used?
Answer: Prazosin. Severe scorpion envenoming causes an autonomic storm; prazosin reduces deaths.
- Atropine: Not recommended.
- Antivenom alone without supportive care: Prazosin is the mainstay where antivenom isn't available.
- Calcium gluconate: No.
- Propranolol: Can worsen heart failure.
2. A man has a large red swollen area around a mosquito bite without fever or pus. What is the best treatment?
Answer: Oral antihistamine. Large local reactions are allergic; antibiotics only if infected.
- Incision and drainage: No.
- IV antibiotics: No.
- Steroid injection: No.
- Oral flucloxacillin: Not infected.
3. After Eid sacrifice, a butcher has fever, muscle pain, bleeding gums and platelets 30,000/µL. What should be suspected?
Answer: CCHF. CCHF spreads by ticks and animal blood: isolate, protect staff, notify.
- Brucellosis: Doesn't cause haemorrhage.
- Typhoid: Doesn't cause bleeding like this.
- Dengue: Possible, but animal blood contact points to CCHF.
- Malaria: Less likely.
4. A 6-year-old in rural Sindh is stung by a scorpion. He develops sweating, vomiting, priapism, hypertension and then pulmonary oedema. Which drug is most helpful for the cardiovascular effects?
Answer: Prazosin. Indian red scorpion (Mesobuthus tamulus) envenoming causes autonomic storm — initial cholinergic signs (sweating, vomiting, salivation, priapism) then adrenergic crisis (hypertension, tachycardia, myocardial dysfunction, pulmonary oedema). Prazosin (α1-blocker) improves outcomes and is the mainstay; scorpion antivenom where available; dobutamine for heart failure. Avoid atropine.
- Atropine: Atropine worsens tachycardia and hypertension.
- Furosemide alone: Furosemide alone is not the key treatment.
- Antihistamine: Antihistamines have no role.
5. Three days after slaughtering a goat for Eid in Quetta, a man has high fever, myalgia, bleeding gums and platelets of 20 × 10⁹/L. What is the most important infection-control step?
Answer: Isolation, barrier precautions. CCHF (Nairovirus, Hyalomma tick) is endemic in Balochistan and Khyber Pakhtunkhwa, peaking around Eid-ul-Adha. Transmission: tick bite, animal blood/tissue, and blood/body fluids of patients (health-worker infections). Features: abrupt fever, myalgia, then bleeding, thrombocytopenia, raised transaminases. Management: isolation with strict contact/droplet barrier precautions, supportive care and blood products, ribavirin early (evidence limited). Post-exposure ribavirin for needlestick contacts.
- Routine open-ward care: Open-ward care risks nosocomial spread.
- N95 mask only, open ward: An N95 mask alone is not enough; isolation is needed.
- Platelet transfusion first: Platelet transfusion does not control transmission.
6. To prove medical negligence, which elements must be shown?
Answer: Duty, breach, harm and causation. Negligence requires: the doctor owed a duty of care, fell below the accepted standard (often judged against what a responsible body of doctors would do), the patient suffered harm, and the breach caused that harm. A known complication without a breach is not negligence.
- Breach and harm only: Harm must also be caused by the breach.
- Duty and breach only: Without resulting harm there is no negligence claim.
- Harm and causation only: A breach of a duty of care must also be shown.
- Duty, harm and intent to harm: Negligence does not require intent.
7. A child with hypocalcaemic tetany, recurrent viral and fungal infections and a cardiac outflow defect most likely has:
Answer: DiGeorge syndrome (22q11 deletion). DiGeorge syndrome: failure of the 3rd and 4th pharyngeal pouches. CATCH-22: Cardiac defects (truncus arteriosus, tetralogy), Abnormal face, Thymic aplasia (T cell deficiency), Cleft palate, Hypocalcaemia (absent parathyroids), 22q11 deletion (FISH).
- Bruton agammaglobulinaemia: B cells absent; bacterial infections.
- Chronic granulomatous disease: Phagocyte defect.
- Wiskott–Aldrich syndrome: Eczema, thrombocytopenia, infections.
- Selective IgA deficiency: Often mild; anaphylaxis to blood products.
References and dose sources
- NICE NG182 — Insect bites and stings: antimicrobial prescribing
- NICE NG95 — Lyme disease
- Cetirizine dosing: Drugs.com: Cetirizine dosage (see also our cetirizine dose page)
- Adrenaline (epinephrine) dosing: Drugs.com: Epinephrine dosage (see also our adrenaline (epinephrine) dose page)
- Flucloxacillin dosing: Drugs.com: Flucloxacillin (international) (see also our flucloxacillin dose page)
- Paracetamol dosing: Drugs.com: Acetaminophen (paracetamol) dosage (see also our paracetamol dose page)
- Lidocaine (lignocaine) dosing: Drugs.com: Lidocaine dosage (see also our lidocaine (lignocaine) dose page)
International guidance is linked where it reflects good practice. Where your hospital’s protocol differs, follow your hospital.