Treatment for Insect Bite Reactions
For insect bite reactions, treatment should focus on symptomatic relief with cold compresses, oral antihistamines, analgesics, and in severe local reactions, a short course of oral corticosteroids. 1
Types of Insect Bite Reactions
Local Reactions
Most insect bites/stings cause mild local reactions characterized by:
- Redness
- Swelling
- Itching and pain
These typically resolve without specific treatment within 24 hours 1.
Large Local Reactions
These are more extensive and include:
- Increasing swelling over 24-48 hours
- Swelling extending >10 cm from the bite site
- Duration of 5-10 days
- Often accompanied by significant itching and pain
Systemic Reactions
These involve symptoms beyond the bite site and can range from mild to life-threatening:
- Cutaneous: urticaria, angioedema
- Respiratory: bronchospasm, upper airway obstruction
- Cardiovascular: arrhythmias, hypotension, shock
- Gastrointestinal: nausea, vomiting, diarrhea
- Neurological: seizures
Treatment Algorithm
1. For Mild Local Reactions
- No specific treatment usually required
- Cold compresses to reduce pain and swelling
- Oral antihistamines for itching
- Oral analgesics for pain
2. For Large Local Reactions
- Cold compresses
- Oral antihistamines
- Oral analgesics
- Short course of oral corticosteroids (although definitive proof of efficacy through controlled studies is lacking) 1
- Important: Antibiotics are NOT indicated unless there is clear evidence of secondary infection 1
3. For Systemic Reactions
- Immediate epinephrine injection (0.01 mg/kg in children up to 0.3 mg; 0.3-0.5 mg in adults) 1, 2
- Supportive therapy
- Transport to emergency department
- For cutaneous-only systemic reactions, antihistamines and close observation may be appropriate 1
Special Considerations
Fire Ant Stings
- Typically cause a sterile pseudopustule within 24 hours
- Keep vesicle intact and clean to prevent secondary infection
- The vesicle is caused by necrotic tissue and is not infected 1
Honeybee Stings
- If a barbed stinger is present, remove it within 10-20 seconds by flicking or scraping it away
- Do not grasp the venom sac as this can inject additional venom 1
Common Pitfalls to Avoid
Misdiagnosing as infection: Large local swelling is caused by allergic inflammation, not infection. Antibiotics are frequently prescribed unnecessarily 1.
Delaying epinephrine: Fatal sting reactions have been associated with delay in administering epinephrine in anaphylactic reactions 1.
Improper stinger removal: Grasping the venom sac can result in injection of additional venom 1.
Overlooking delayed reactions: Some allergic reactions may have delayed onset (1-2 weeks after the sting) 3.
Failing to recognize risk for future reactions: Patients who have had large local reactions have up to 10% risk of eventually developing a systemic reaction to subsequent stings 1.
For patients with history of systemic reactions to insect stings, referral to an allergist-immunologist is recommended for consideration of venom immunotherapy, which can significantly reduce the risk of future systemic reactions 1.