Scorpion Sting - Treatment

Fig. 20.53 Common Centruroides scorpion (Andrews' Diseases of the Skin)

Step 1 - Identify the Scorpion (Species Matters)

• Harrison's Principles of Internal Medicine 22E (2025), p. 3778

Step 2 - Severity Assessment

• Most stings (non-dangerous species, adults): Local pain, paresthesia, edema, burning - resolve within hours. These can be managed at home.
• Severe envenomation signs (especially Centruroides in US): Cranial nerve dysfunction (blurred vision, abnormal eye movements, slurred speech, profuse salivation), skeletal muscle hyperexcitability, restlessness, diaphoresis, tachycardia, arrhythmias, hypertension, rhabdomyolysis.
• Tap test: Paresthesia accentuated by tapping the sting site is characteristic of C. sculpturatus envenomation.
• Children and the elderly are at highest risk of fatal respiratory arrest.

Treatment by Category

1. Mild / Non-Dangerous Species

• Ice packs to the sting site
• Oral analgesics (NSAIDs or acetaminophen)
• Oral antihistamines (for local reaction / allergic component)
• Observe at home; return if neurological signs develop
• Harrison's 22E, p. 3778

2. General / All Significant Envenomations

• Keep the patient calm
• Apply pressure dressings and cold packs to reduce venom absorption
• Stabilize airway and vital signs
• Tetanus prophylaxis when appropriate
• Cleanse and disinfect the wound

3. Neurological / Neuromuscular Symptoms (e.g., Centruroides)

• Midazolam (IV, continuous infusion) - drug of choice to reduce agitation and involuntary muscle movements
• Sedatives or opiates may be used but require close respiratory monitoring
• Antivenom (see below)
• Harrison's 22E, p. 3778

4. Cardiovascular Complications (e.g., catecholamine storm species)

• Hypertension / Pulmonary edema: nifedipine, nitroprusside, hydralazine, or prazosin
• Bradydysrhythmia: atropine
• Note: Steroids, antihistamines, calcium channel blockers, and diuretics should be avoided in cardiac complications from envenomation - they can worsen outcomes due to negative cardiac effects (UN DHMOSH guidelines)

5. Antivenom (Antivenin)

• Represents the most effective intervention for dangerous species
• USA: FDA-approved equine-derived C. sculpturatus IgG F(ab')₂ antivenin - IV administration rapidly reverses cranial-nerve dysfunction and muscular symptoms
• Commercially prepared antivenins also available in several other countries for local dangerous species (North Africa, Middle East, Brazil, India, South Africa)
• Antivenom criteria are based on: severity of envenomation, age of patient (more dangerous in children), and time elapsed since sting
• Transfer patients with moderate-to-severe symptoms (grades 3-4) to a center with antivenom capability if not locally available
• Harrison's 22E, p. 3778; Andrews' Diseases of the Skin

6. Special Considerations - Hemiscorpius lepturus (Iran/adjacent regions)

• Initial sting may be deceptively mild
• Monitor closely from day 1 onward for hemolysis, hemoglobinuria, tissue necrosis, and acute kidney injury
• Supportive management of AKI as needed

Avoid the Following

• Negative-pressure extraction devices - utility not established for scorpion stings
• Calcium channel blockers, steroids, antihistamines, diuretics - can worsen cardiac complications in serious envenomations

Disposition

• Home: Adults with local pain only, no systemic signs
• Emergency Department / Hospital: Any patient with systemic symptoms, children stung by known dangerous species, or any sting where species is uncertain in a high-risk area
• Aggressive supportive care combined with judicious use of antivenom can eliminate deaths from severe envenomations

• Harrison's Principles of Internal Medicine 22E (2025), pp. 3778-3779
• Andrews' Diseases of the Skin - Clinical Dermatology, p. (block 6)
• UN DHMOSH Guidance for Prevention & Management of Scorpion Stings (2026)