How should I manage an insect bite, including first‑aid steps, pain and itch relief, and when to use epinephrine or antibiotics?

Insect Bite Management

For uncomplicated insect bites, immediately wash the area with soap and water, remove any visible stinger within 60 seconds by scraping or plucking, then apply cold compresses and give oral antihistamines for itch relief—but if any systemic symptoms appear (difficulty breathing, widespread hives, throat swelling, lightheadedness), administer intramuscular epinephrine 0.3-0.5 mg immediately into the anterolateral thigh and activate emergency services. 1, 2, 3

Immediate First-Aid Steps

Stinger Removal (If Present)

• Remove any visible stinger within the first 60 seconds by either scraping with a fingernail or plucking it out—the method doesn't matter, but speed is critical since venom continues to be delivered for up to 60 seconds. 1, 2
• Never grasp and pull the venom sac, as this injects additional venom into the skin. 1, 4

Initial Wound Care

• Wash the bite/sting area with soap and water immediately after stinger removal. 1, 2
• This simple step helps prevent secondary infection and removes surface contaminants. 1

Treatment Algorithm by Reaction Severity

Local Reactions (Most Common Presentation)

Pain Management:

• Apply ice or cold packs directly to the bite site for local pain relief and to reduce swelling. 1, 2
• Administer over-the-counter acetaminophen or NSAIDs (ibuprofen) for pain control. 1, 2

Itch Relief:

• Give oral antihistamines to alleviate local itching—this is supported by clinical trial data for mosquito bites and expert consensus for bee/wasp stings. 1, 2
• Apply topical corticosteroids directly to the sting site for local inflammation and itching. 1, 2

Critical Pitfall: Do NOT prescribe antibiotics for routine swelling—the inflammation is allergic, not infectious, and antibiotics are unnecessary unless clear signs of secondary bacterial infection develop (progressive redness, purulent discharge, fever, increasing pain). 1, 5, 4

Large Local Reactions (Extensive Swelling)

• Continue cold compresses and oral antihistamines as the foundation of treatment. 1, 5, 4
• Initiate a short course of oral corticosteroids promptly within the first 24-48 hours to limit progression of swelling, though controlled trial evidence is limited. 1, 2, 5, 4
• These reactions typically peak at 24-48 hours and may persist for 5-10 days—this is IgE-mediated allergic inflammation, not infection. 5, 4
• Elevate the affected limb if swelling is significant. 4

Anaphylaxis (Life-Threatening Emergency)

This is the most critical scenario where delayed treatment causes mortality:

• Immediately administer intramuscular epinephrine 0.01 mg/kg (up to 0.3 mg) in children or 0.3-0.5 mg in adults into the anterolateral thigh—this is the ONLY first-line treatment. 1, 2, 4, 3
• Intramuscular injection in the anterolateral thigh achieves more rapid and higher plasma concentrations than subcutaneous or arm injection. 1
• Activate emergency medical services immediately—do not delay. 1, 2
• Be prepared to repeat epinephrine dosing if symptoms persist or recur after 5-15 minutes. 1, 2, 4

Signs of anaphylaxis include: difficulty breathing, tongue or throat swelling, lightheadedness (hypotension), vomiting, disseminated hives beyond the sting site, bronchospasm, or cardiovascular collapse. 1, 3

Critical Pitfall: Antihistamines and corticosteroids are NOT substitutes for epinephrine in anaphylaxis and play no role in acute management—delayed epinephrine administration is associated with fatal outcomes. 1, 2, 4 There is no contraindication to epinephrine use in a life-threatening situation, even in patients with cardiovascular disease. 1, 4

When to Use Epinephrine

Epinephrine is indicated for:

• Any systemic symptoms beyond the local sting site (widespread urticaria, angioedema, respiratory distress, hypotension, gastrointestinal symptoms). 1, 2, 4, 3
• Patients with a history of anaphylaxis should self-administer their epinephrine autoinjector at the first sign of systemic symptoms. 1, 2
• First aid providers should assist with autoinjector administration if the patient requires help. 1

When to Use Antibiotics

Antibiotics are indicated ONLY when:

• Clear signs of secondary bacterial infection are present: progressive redness, increasing pain, purulent discharge, fever, warmth and tenderness. 5, 4
• Secondary infection is uncommon following insect bites/stings. 5

Special consideration for fire ant stings: These characteristically produce a sterile pseudopustule within 24 hours—this is necrotic tissue, NOT infection. Leave the vesicle intact and keep clean to prevent secondary infection; do not prescribe antibiotics. 1, 4

Special Circumstances

Eye Stings

• Any sting to the eye itself (not eyelid or periorbital area) requires immediate evaluation by a trained medical professional due to risk of permanent vision loss. 1, 2

Massive Envenomation

• Multiple stings (typically >100 for honeybees, >20 for large hornets) can cause toxic reactions from massive envenomation, even in non-allergic individuals, and may be clinically indistinguishable from allergic reactions. 1, 2, 4

Post-Treatment and Prevention

Epinephrine Autoinjector Prescription

• All patients who experience any systemic reaction must receive an epinephrine autoinjector prescription and training on self-administration before discharge. 1, 2, 4
• Consider prescribing two autoinjectors, as some patients require more than one dose during anaphylaxis. 4

Allergist Referral

• Refer all patients with systemic reactions (including isolated widespread urticaria) to an allergist-immunologist for venom-specific IgE testing and consideration of venom immunotherapy (VIT). 1, 5, 4
• VIT reduces the risk of subsequent systemic reactions from 25-70% down to <5% and is extremely effective. 4
• Patients with recurrent large local reactions and unavoidable exposure may also benefit from allergist referral. 4
• Testing may be temporarily non-reactive within the first few weeks after a systemic reaction and may require retesting in 6 weeks. 4

Avoidance Measures

• Avoid bright clothing and scented products when outdoors. 5
• Exercise caution around bushes, outdoor eating areas, and known nesting sites. 5
• Have known nests removed by professionals. 5