<s>[INST] Hi. About 2 weeks ago, I started to itch along my arms and hands. I noticed about two bumps on my hand and several on my arms. I thought they were mosquito bites. They were very itchy and hurt just a little but went away after a couple of days. They left dark spots however, which I thought a bit odd, as a mosquito bite usually would not leave such dark marks on me. Then about last Thursday, I started to itch under my chin. A swelling that made me look like I had a double chin developed but by Monday, it had gone down and has left a dark mark. Last night, my two upper arms started to itch and I have two large swellings on each arm now! What could this be? Can someone help please. [/INST] HIThank choosing HCMI would be happy to answer your query, from the history given here I could say that this is the allergic condition and it can be due to many things among that the first could be auto-immune response, second environmental, food allergy, medicine allergy, psychological, and others, in rare case it could be due to systemic disease and all of these condition anti-histamine and steroid can be tried like Tab Levocetirizine 10 mg three times in day, Tab Dexamethasone 10 mg three times in day for 5 days, hope this helps you. </s>