How should an ant bite be managed in an infant?

Management of Ant Bites in Infants

For simple local ant bite reactions in infants, apply cold compresses and administer age-appropriate oral antihistamines; however, immediately administer intramuscular epinephrine 0.01 mg/kg (maximum 0.3 mg) into the anterolateral thigh if any systemic symptoms develop, as delayed epinephrine administration is associated with fatal outcomes. 1, 2

Initial Assessment and Stinger Removal

• Remove any visible stinger within 10-20 seconds by scraping or flicking it away with a fingernail to prevent additional venom injection 2
• Never grasp or pull the venom sac, as this forces more venom into tissue 2
• Rapidly assess for signs of systemic reaction (urticaria beyond the bite site, angioedema, respiratory distress, or cardiovascular symptoms) 1

Treatment Based on Reaction Type

Simple Local Reactions (Most Common)

• Apply cold compresses or ice packs to reduce local pain and swelling 1, 2
• Administer oral antihistamines (cetirizine preferred over diphenhydramine due to minimal sedation in children) to reduce itching 2, 3
• Provide age-appropriate oral analgesics (acetaminophen or ibuprofen) for pain relief 2
• Most local reactions require no treatment and resolve spontaneously 1

Large Local Reactions (Extensive Swelling Beyond Bite Site)

• Initiate a short course of oral corticosteroids promptly within the first 24-48 hours to limit progression of allergic inflammation 1, 2
• Continue cold compresses and oral antihistamines 1, 2
• Do not prescribe antibiotics, as the swelling is caused by allergic inflammation, not infection 1

Fire Ant-Specific Considerations

• Leave the characteristic sterile pseudopustule intact and keep it clean to prevent secondary infection 1
• The vesicle that develops within 24 hours is caused by necrotic tissue from piperidine alkaloids, not infection 1, 4
• Secondary bacterial infection is unusual but can occur if the pustule is disrupted 1

Emergency Management of Systemic Reactions

Immediate Life-Threatening Treatment

• Administer intramuscular epinephrine 0.01 mg/kg (maximum 0.3 mg in infants) into the anterolateral thigh immediately for any systemic symptoms 1, 2, 5
• Epinephrine is the ONLY first-line treatment for anaphylaxis and has no contraindication in life-threatening situations 2, 5
• Never delay epinephrine in favor of antihistamines or corticosteroids, as fatal reactions are associated with delayed epinephrine administration 1, 5
• Intramuscular injection in the anterolateral thigh achieves faster and higher plasma concentrations than subcutaneous or arm injection 1, 3

Supportive Care

• Provide supportive therapy including oxygen, intravenous fluids, and cardiac monitoring as needed 1
• Transport to emergency department for observation, as reactions can be biphasic or protracted 1
• Repeat epinephrine dosing may be required for persistent or recurrent symptoms 5

Important Distinction for Infants

• Systemic reactions in children limited to skin only (widespread hives/angioedema) are not considered anaphylactic reactions by guideline definition 1
• However, these cutaneous systemic reactions still warrant antihistamines and close observation 1, 3

Post-Acute Management

For Any Systemic Reaction

• Prescribe an epinephrine autoinjector and train caregivers on proper use and emergency indications 2, 5
• Refer to an allergist-immunologist for venom-specific IgE testing and consideration of venom immunotherapy (VIT) 2, 5

Venom Immunotherapy Considerations

• VIT is generally not necessary in children ≤16 years who experienced only cutaneous systemic reactions 3, 5
• VIT is recommended for infants who experienced respiratory or cardiovascular symptoms, as it reduces subsequent systemic reaction risk to less than 5% 5

Critical Pitfalls to Avoid

• Never attribute extensive swelling to infection and prescribe unnecessary antibiotics—large local reactions are allergic inflammation 1
• Do not rupture fire ant pustules, as this increases secondary infection risk 1
• Be aware that massive envenomation (typically >100 stings) can cause toxic multi-organ reactions even without allergy 2, 5
• Fatal anaphylaxis to ant stings in infants has been documented, emphasizing the importance of rapid epinephrine administration 6

Prevention Strategies

• Infants in fire ant-infested areas should wear socks, which provide significant protection by reducing the number of ants reaching skin and delaying sting time 7
• Cotton tights may provide additional lower extremity protection 7
• Insect repellents are ineffective at deterring fire ants from stinging 7