Hello, I don t think this is related to HIV or an STD. I do think that you should be tested for them just to be safe, regardless, for your health. Something did come to mind though when you mentioned this rash and itching. Do you have any lines in between your fingers? Sometimes scabies can be acquired from other people, especially if they have poor hygiene. Scabies is a little mite. If the rash continues and you notice little track marks inbetween your fingers this may be the case. Perhaps it is an allergic reaction? Maybe to her soap or detergent? In that case you could use some hydrocortisone cream to clear it up.