When the hands are bitten by insects, resulting in swelling, usually due to insect bites that cause dermatitis or secondary infection, you should promptly observe your own symptoms and react quickly according to the environment you are in. If there is a clean water source can promptly wash the bite site, if the bite bleeds should promptly squeeze out the blood, and then wash the wound with warm, cool water. If you have iodophor, alcohol, anti-inflammatory ointment and other topical antiseptic and anti-inflammatory drugs on hand, you can apply them to the swelling to quickly sterilize and reduce inflammation and facilitate the swelling. Generally speaking, if the bite site is only mildly swollen, the use of these topical medications can be treated, and observe whether the swelling can be eliminated on its own. If the swelling persists, or is accompanied by systemic allergic reactions, fever, severe pain and other symptoms, then you should quickly go to the hospital for diagnosis and treatment. After arriving at the hospital, you should quickly register with the emergency department, and the doctor will conduct blood tests to determine the patient’s physical condition and give the corresponding treatment, so as not to delay the treatment. Also note that if you are bitten and swollen outdoors, it is recommended that you quickly leave the environment you are in first to prevent secondary bites from insects.