Treatment for Insect Bites
For uncomplicated insect bites, cold compresses, oral antihistamines, and topical corticosteroids should be used as first-line treatment, with antibiotics reserved only for cases showing signs of infection or in high-risk patients. 1
Assessment of Bite Severity
Before initiating treatment, it's essential to determine the severity of the reaction:
Local Reactions (Most Common)
- Characterized by redness, swelling, itching, and pain limited to the bite site
- May include large local reactions (swelling >10cm in diameter, lasting 5-10 days) 2
Systemic Reactions
- Range from mild to life-threatening
- Include symptoms beyond the bite site: urticaria, respiratory symptoms, bronchospasm, upper airway obstruction 2
- Require immediate medical attention, especially if signs of anaphylaxis develop
Treatment Algorithm for Insect Bites
1. For Uncomplicated Local Reactions:
- Clean the area with mild soap and water 1
- Apply cold compresses or ice packs wrapped in a thin towel for 15-20 minutes to reduce pain, swelling, and inflammation 1
- Use topical corticosteroids like hydrocortisone to temporarily relieve itching and inflammation 3
- Administer oral antihistamines to reduce itching 1
- Consider topical lidocaine (4-5% formulation) for pain management 1
2. For Large Local Reactions:
- Follow the steps for uncomplicated local reactions
- Monitor for 24-48 hours as these reactions typically increase in size during this period 2
- Consider oral corticosteroids for severe swelling 1
3. For Systemic Reactions/Anaphylaxis:
- Administer epinephrine intramuscularly in the mid-outer thigh (adult: 0.3-0.5 mg; pediatric: 0.01 mg/kg up to 0.3 mg), repeating every 5 minutes if needed 1, 4
- Position patient appropriately:
- Supine with legs elevated if experiencing cardiovascular symptoms
- Position to optimize breathing if respiratory distress or vomiting 1
- Administer oxygen for prolonged reactions or patients requiring multiple epinephrine doses 1
- Establish IV access for fluid resuscitation with normal saline for hypotension 1
- Administer corticosteroids (methylprednisolone 1-2 mg/kg IV) to prevent protracted anaphylaxis 1
- Use bronchodilators (albuterol 2.5 mg nebulized) for persistent bronchospasm 1
Special Considerations
High-Risk Patients Requiring Closer Monitoring:
- Immunocompromised individuals
- Asplenic patients
- Those with advanced liver disease
- Patients with history of severe anaphylaxis 1
High-Risk Bite Locations:
- Hands, face, genitals
- Areas near joints 1
When to Consider Antibiotics:
- Signs of infection (increasing redness, warmth, swelling, purulent discharge)
- High-risk patients as mentioned above
- First-line antibiotic: Amoxicillin-clavulanate 875/125 mg twice daily 1
Prevention Strategies
- Carry injectable epinephrine if history of systemic reaction to insect stings 2
- Wear protective clothing (long pants, long sleeves, closed shoes) 1
- Use insect repellents containing DEET 1
- Apply permethrin spray on clothing 1
- Remove insect nests professionally 1
- Avoid bright colors or flowery prints that attract insects 1
Follow-Up Recommendations
- Return if symptoms worsen despite 48 hours of treatment
- Seek emergency medical attention immediately if signs of anaphylaxis develop
- Consider venom immunotherapy (VIT) for patients with history of systemic allergic reactions to insect stings 1
Common Pitfalls to Avoid
- Avoid applying heat to insect bites as it may increase inflammation and venom absorption, despite a recent study suggesting potential benefits of concentrated heat application 1, 5
- Avoid using meat tenderizer due to limited evidence for effectiveness 1
- Avoid pressure immobilization bandages which may increase venom release 1
- Don't delay epinephrine administration in cases of anaphylaxis 1, 4
- Don't routinely prescribe antibiotics for uncomplicated insect bites 1