<s>[INST] Hello, my younger sister woke up this morning with a painful mark on her wrist. Its white in the centre and has a red ring around it, and spans about 2cm across. Its not scaly and itchy like it would be if it was ringworm, and its completely flat. She says nothing has burnt her or bitten her or anything. Any ideas what this could be? Thank you! [/INST] Hi Welcome to Chat Doctor Forum Looks like your sister has developed a lesion of Vector dermatitis.also known as Panders dermatitis. Panders dermatitis is a peculiar, irritant contact dermatitis characterized by a sudden onset of red lesions on exposed areas of the body. The disease is provoked by an insect belonging to the genus Panders. Such lesions due to insect bite usually have a history of sudden overnight development. You need to apply an antibiotic/steroid combination cream over the lesion (something like flutist, Unibet) twice a day. Take oral antihistamine like levocetrizine once a day to decrease the redness Do not use any moisturizer or lipstick over the lips till the time the lesion heals Hope it helps To wish your sister speedy recovery Chat Doctor.  </s>