What symptoms appear after a mosquito bite?

After a mosquito bite, the following symptoms commonly occur: 1. Skin reaction: The bitten area may develop erythema, papules, or wheals, sometimes with pinpoint-sized red petechiae, accompanied by itching or mild swelling and pain. Some individuals may experience more severe reactions, including swollen red plaques or bruises. 2. Allergic reaction: Antigenic components in mosquito saliva may trigger allergic reactions in some individuals, presenting as increased local swelling and redness, and in severe cases, systemic urticarial papules, hoarseness, throat swelling, dizziness, or nausea. 3. Secondary infection: Scratching the bite area may damage the skin and lead to infection, causing symptoms such as pus discharge and increased redness and swelling. 4. Systemic symptoms: In rare cases, if the mosquito carries a specific virus (such as Japanese encephalitis virus), systemic symptoms such as fever, headache, fatigue, and nausea may occur after a bite, although this is uncommon.