What medication is used to treat a mosquito bite?

Treatment of Mosquito Bites

For mosquito bite itching and local reactions, use oral antihistamines and topical corticosteroids, which have clinical trial support for efficacy. 1

Symptomatic Treatment Approach

First-Line Medications

Oral antihistamines are the primary treatment for mosquito bite itching and local reactions:

• Cetirizine has been specifically shown to be effective against mosquito bite wealing and pruritus when given prophylactically 2, 3
• Ebastine 10-20 mg significantly decreases bite lesion size and pruritus, particularly for immediate symptoms at 15 minutes post-bite 4
• These medications work by blocking the IgE-mediated type I allergic reaction that causes the immediate wheal-and-flare response 2

Topical corticosteroids (such as hydrocortisone 1%) are supported by clinical trials for local itching: 1, 5

• Apply directly to the bite site to reduce inflammation
• Particularly useful for the delayed papular reactions that develop hours after the bite

Adjunctive Symptomatic Measures

For pain and swelling management:

• Apply cold compresses or ice packs to reduce local pain and swelling 1, 6
• Use oral over-the-counter analgesics such as acetaminophen or ibuprofen for pain relief 1

For large local reactions (swelling >10 cm):

• A short course of oral corticosteroids may be considered in severe cases, though definitive proof of efficacy through controlled studies is lacking 1, 6
• These reactions typically increase in size for 24-48 hours and take 5-10 days to resolve 1

Important Clinical Pitfalls

Avoid unnecessary antibiotics:

• Antibiotics are not indicated for mosquito bites unless there is clear evidence of secondary bacterial infection 1, 6
• The swelling and redness are caused by mediator release from the allergic reaction, not infection—this is a common misdiagnosis 1

Recognize when escalation is needed:

• Most mosquito bite reactions are simple local reactions requiring only symptomatic treatment 1
• Systemic reactions (urticaria, angioedema, respiratory symptoms, hypotension) are very rare but require emergency treatment with intramuscular epinephrine 0.3-0.5 mg in adults 6, 7, 2
• Patients with history of systemic reactions should carry emergency epinephrine and be referred to an allergist-immunologist 6

Prevention Strategies

For patients with recurrent problematic reactions:

• Use DEET-containing insect repellents on exposed skin (most effective mosquito repellent available) 6
• Wear long-sleeved clothing and long pants, especially during evening hours 1, 6
• Apply permethrin to clothing for additional protection 1, 6
• Consider prophylactic oral antihistamines before exposure in highly sensitive individuals 2, 3, 4