how do you deal with someone who is always complaining about being sick or hurt...?

ugh... my sister is one of these hypocondriac attention whores. she's always sick, or in pain and constantly talks about it. the thing is...she isnt direly ill, or seriously injured. im talking about colds and common stuff we all deal with. she also lost a considerable amount of weight and is always fishing for people to say she's "too skinny". she isnt. my question is, how do i deal with this? i am very close to her and try to change the subject when she starts up on her misery, but shes becoming relentless.
ok, here... she works for our mother btw:

me: did you watch the rep convention last night?
me: or any of it?
Kim : i gues i have to be dead in order to get out of here...this is bulll shit
me: sucks cuz u just had all those days off for your ribs
Kim : well the excuse is "theres no one to replace you right now" bull...i feel like i am dying

me: well im sorry, no offense but at any job, most ppl dont take days off for being sick. maybe once or twice a year at most. im not agreeing just saying....it isnt unlike any other job
Kim : well most jobs i had...when i was sick they would send me home


Kim : ill just hold it in i guess....
me: i understand what you are saying. can u take day quil?
Kim : I cant drink meds i get sick...plus the meds im on make me sick as it is
Kim : my stomach is in a knot
Kim : i could eat my taco bell at all
me: you can buy it in pill form
Kim : couldnt*
me: they work well