Anaphylaxis from mosquito bites

Redness, itching and swelling limited to the area around a mosquito bite are local reactions and do not by themselves describe anaphylaxis. Anaphylaxis affects the body beyond the bite site and may present with wheezing, throat or tongue swelling, widespread hives, repeated vomiting, dizziness, confusion or collapse. Marked swelling around a bite can still be uncomfortable and deserves routine medical advice if it is worsening, but emergency action is driven by breathing, circulation or rapidly spreading symptoms.

If anaphylaxis is suspected, use the person’s prescribed epinephrine auto-injector without delay and call emergency services. Follow the device directions and do not substitute an antihistamine for epinephrine. Keep the person lying flat with raised legs when possible; support them sitting if breathing is difficult, and place them on their side if they are vomiting or unconscious but breathing. Do not allow walking or sudden standing. Follow the written emergency plan regarding another prescribed dose if severe symptoms persist or return.

Call for emergency help after a mosquito bite if there is noisy or difficult breathing, wheezing, throat tightness, a hoarse voice, tongue swelling, faintness, collapse or a rapid combination of symptoms in different body areas. Medical assessment remains necessary even when epinephrine brings improvement, as symptoms can return. Begin CPR if the person is unresponsive and not breathing normally, provided you can do so, and follow instructions from the emergency dispatcher.

Describe the bite, the sequence of symptoms, treatments used and any previous reactions. Photos of the skin reaction can help if safely taken, but they should never delay emergency care. Ask whether referral for allergy assessment is suitable, whether you need prescribed auto-injectors, and how to practise with a trainer device. Discuss repellent, protective clothing and screens as exposure-reduction measures, plus safe storage of medicine in hot weather.