What is the recommended treatment for a patient with midge bites, considering potential allergic reactions and infection?

Treatment of Midge Bites

For midge bites, treatment is primarily symptomatic with cold compresses and oral antihistamines; antibiotics are not indicated unless there is clear evidence of secondary bacterial infection, and epinephrine should be immediately available if systemic symptoms develop. 1, 2

Initial Management of Local Reactions

Immediate Measures

• Apply cold compresses to the bite site to reduce local pain, swelling, and slow venom spread 1, 3, 2
• Administer oral antihistamines to reduce itching, pain, and inflammation associated with the cutaneous reaction 1, 3, 2
• Use oral analgesics for pain management as needed 1, 2
• Remove any visible stinger by scraping or flicking (though midges typically don't leave stingers like bees) 3

Large Local Reactions

• Oral corticosteroids should be promptly initiated for patients with extensive swelling and a history of large local reactions, though definitive controlled trial evidence is lacking 1, 2
• Elevate the affected limb if swelling is significant to reduce edema and improve circulation 3
• Continue cold compresses and antihistamines 1, 2

Critical Pitfall: Do NOT Prescribe Antibiotics Routinely

The swelling that occurs in the first 24-48 hours is caused by allergic inflammation from mediator release, NOT infection, and therefore does not require antibiotic therapy. 1, 2 This is one of the most common errors in managing insect bites.

When Antibiotics ARE Indicated

Antibiotics should only be prescribed if there is clear evidence of secondary bacterial infection, including: 2

• Progressive redness beyond the initial reaction
• Increasing pain after the first 48 hours
• Purulent discharge
• Fever
• Warmth and tenderness suggesting cellulitis

Managing Potential Allergic Reactions

Risk Assessment

• Patients with previous large local reactions have approximately 5-10% risk of eventually experiencing a systemic reaction to subsequent bites 1, 3
• Most midge bites cause only mild local reactions that are self-limiting 2, 4

Emergency Preparedness

Antihistamines and corticosteroids are NOT substitutes for epinephrine in systemic/anaphylactic reactions. 1 If any signs of systemic reaction develop, including:

• Difficulty breathing or laryngospasm
• Hypotension or syncope
• Widespread urticaria beyond the bite site
• Facial or throat swelling
• Dizziness or altered consciousness

Immediately administer epinephrine 0.3-0.5 mg intramuscularly in the anterolateral thigh (0.01 mg/kg in children, up to 0.3 mg) and transport to the emergency department 1, 3, 5

Epinephrine Autoinjector Prescription

• Consider prescribing an epinephrine autoinjector for patients with previous large local reactions, particularly those with frequent unavoidable exposure to midges or living in endemic areas 1, 3
• Patients and caregivers must be taught how and when to administer epinephrine 6
• There is no contraindication to epinephrine use in life-threatening anaphylaxis, even in patients with cardiovascular disease 6

Specialist Referral Considerations

When to Refer to Allergist

Referral to an allergist-immunologist should be considered for: 1, 3, 2

• Patients with systemic reactions (respiratory symptoms, cardiovascular symptoms, or widespread urticaria)
• Patients with severe large local reactions and frequent unavoidable exposure
• Patients experiencing vascular compromise from severe local swelling
• Consideration of venom immunotherapy

Venom Immunotherapy

• Venom immunotherapy significantly reduces the size and duration of large local reactions and is highly effective (90-98%) in preventing systemic reactions 1, 4, 7
• Immunotherapy may be considered for patients with unavoidable frequent exposure and history of severe reactions 1, 3

Special Considerations for Forcipomyia taiwana (Biting Midge)

For patients in Taiwan and Southern China where Forcipomyia taiwana is endemic: 8, 9

• Approximately 48% of exposed individuals develop immediate IgE-mediated reactions 8
• Major allergens include For t 1 (24 kDa), For t 2 (35 kDa), and For t 3 (64 kDa) proteins 8
• Reactions are characterized by intense pruritus and can prevent regular outdoor activities 10

Prevention Strategies

Educate patients on avoidance measures: 6, 2

• Avoid areas with high midge activity, particularly at dawn and dusk
• Wear long pants, long-sleeved shirts, and socks when in wooded or rural areas
• Avoid brightly colored clothing and strongly scented products
• Use appropriate insect repellents (though standard repellents may be less effective against midges)
• Have known breeding sites near the home addressed by professionals