Treatment of Insect Bites on the Legs
For simple insect bites on the legs, apply cold compresses and oral antihistamines for symptomatic relief; topical hydrocortisone can be used for persistent itching, and reserve oral corticosteroids for severe large local reactions with extensive swelling. 1
Initial Assessment and Stinger Removal
- If a barbed stinger is visible, remove it within 10-20 seconds by flicking or scraping it away with a fingernail to prevent additional venom injection 1
- Avoid grasping the venom sac, as this injects additional venom 1
- Most insect bites cause only transient local reactions (redness, swelling, itching, pain) requiring minimal or no treatment 1
Symptomatic Treatment Algorithm
For Mild Local Reactions:
- Apply cold compresses to reduce local pain and swelling 1
- Oral antihistamines help reduce itching 1
- Oral analgesics for pain relief 1
- Topical hydrocortisone (0.5-1%) can be applied 3-4 times daily for persistent itching in adults and children ≥2 years 2
For Large Local Reactions (>10 cm diameter, lasting days):
- Continue cold compresses and oral antihistamines 1
- Consider a short course of oral corticosteroids for severe cases with extensive erythema and swelling persisting 24-48 hours 1
- The swelling is caused by allergic inflammation, not infection, so antibiotics are not indicated unless secondary infection develops 1
Important Clinical Pitfalls
Do not prescribe antibiotics for initial swelling or lymphangitis - this is a common misdiagnosis, as the inflammation is mediator-driven rather than infectious 1. Secondary infection is uncommon and should only be treated if there is clear evidence (purulence, fever, spreading cellulitis) 1.
For fire ant bites specifically, the sterile pseudopustule that forms within 24 hours should be left intact and kept clean rather than drained, as it contains necrotic tissue and is not infected 1.
When to Escalate Care
Immediate epinephrine administration is required if systemic symptoms develop (urticaria beyond the bite site, angioedema, bronchospasm, throat swelling, hypotension) 1. The dose is 0.01 mg/kg in children (maximum 0.3 mg) and 0.3-0.5 mg in adults, administered intramuscularly in the anterolateral thigh 1.
Refer to an allergist-immunologist any patient who develops systemic reactions beyond the local bite site, as they may benefit from venom immunotherapy 1.
Alternative Approaches
Concentrated heat application (via medical devices) shows promise for rapid symptom relief, with studies demonstrating 57% itch reduction within 1 minute and 81% reduction at 5-10 minutes for mosquito bites 3. However, this remains an adjunctive option rather than first-line therapy 4, 3.