What causes hives after a mosquito bite?

Urticaria caused by mosquito bites may indicate a decline in the patient’s immune function. Clinically, it manifests as solid papules of varying sizes, often accompanied by vesicles that may be scattered or multiple, along with varying degrees of pruritus. Treatment is primarily symptomatic and desensitizing: oral antihistamines such as chlorpheniramine and epinastine are commonly used; topical treatments include dampness-removing and itch-relieving washes (e.g., Chu Shi Zhi Yang Xi Ji) or Sichuan Phellodendron itch-relieving wash (Chuan Bai Zhi Yang Xi Ji). Patients should minimize bathing-related irritation and avoid dietary triggers such as fishy, spicy, or pungent foods.