A week after being bitten by a centipede, a large piece of swelling is considered to be insect bite dermatitis, which needs to be treated with medication, including local medication and systemic medication. 1. Local medication: you can use glycerine lotion to play an astringent role, if the effect is not good, you can also apply glucocorticoid drugs, such as hydrocortisone butyrate cream, dexamethasone cream, trimethoprim cream and so on. 2. Systemic medication: antihistamines can be used to shorten the course of the disease and improve the therapeutic effect, mainly cetirizine, loratadine, ibastine, ipecac, and so on. If there is a combination of bacterial infection, you also need to take oral antibiotic drugs, such as amoxicillin, levofloxacin, cefixime. The disease is serious use of glucocorticoid drugs, such as dexamethasone, prednisone and so on. After being bitten by a centipede for a week, a large piece of swelling should be promptly consulted and treated according to the doctor’s instructions. All of the above medications should be used under the guidance of a doctor, avoid self-medication.