Ive been on warfarin for 18 years at 15 mg ,INR 3.2 and in the la...

Ive been on warfarin for 18 years at 15 mg ,INR 3.2 and in the last 3 years I have doveloped a really itchy rash(below knee) that just wont go away.It often becomes infected and has to be treated with antibiotics.The infection goes away but the rash keeps on itchin! I found teatree oil and grapeseed oil mixed together ease it but i need a cure before I chew it off at the knee.Sometimes I scratch in my sleep ,and the result is a venous ulcer.(the last one took 18 months 2 weeks and 3 days to heal).Any ideas?