A bug bite with redness and itchiness is clinically known as bug bite dermatitis or papular urticaria. If the itch is stronger you can first stop the itch by emergency treatment, and later, depending on the severity of the symptoms, choose local topical ointment treatment or systemic treatment to help relieve: 1. Emergency treatment: you can first use alkaline substances to help relieve the itchiness, such as soap and water can neutralize the acid left after the bug bite, thus playing the effect of stopping the itch. Local cold and wet compresses can also be applied, which can inhibit the activity of cells, slow down the conduction of nerve impulses, reduce the sensitivity of nerve endings, and thus reduce itching; 2. Local treatment: apply topical ointments containing mint, aloe vera, ice chips, or hormonal ointments such as mometasone furoate cream and hydrocortisone butyrate cream. There are also some Chinese herbal ingredients, such as dampicol ointment, Qingpeng ointment, etc., which can relieve itching; 3, systemic smelting treatment: systemic treatment for patients with serious conditions, available antihistamines, such as benadryl, iproniazid, chlorpheniramine maleate, loratadine, cetirizine hydrochloride, etc. In case of heavy local allergic reaction with allergic lymphangitis, hormones can be applied intravenously or intramuscularly, such as methylprednisolone, trenbolone, dexamethasone, etc. In case of combined infection, antibiotics such as roxithromycin and azithromycin can be used.