My Lupus rash never really itched, but some people do have ones that itch. Sometimes it is because our meds dry out our skin.
Besides the hydrocortisone cream couchtater suggested, also try a moisturizing lotion/cream and make sure you are properly hydrated.
Lynnwood, Lupus & Sjogren's Moderator, Dx: 2002DIAGNOSING LUPUS & HW's LUPUS 101
"Life is far too important to be taken seriously." - Oscar Wilde