What Causes Itchy Lack Patches With Blisters On Legs?

More than 25yrs I'm having skin problem, black patches on my legs sometime very itchy, specially in hot season.some time i found small bubbles containing water(small amout of liquid)in that.I was taking tratment from mumbai's best & well known dermetologist. she gies me medicene injection on that patches.but no use. she told me this happen reason pscyological, she advice me to stop thinking, live worried free life.this happen to very few people proportion is like one in ten thosand or evan more.can you please advice me what to do? my mail id is YYYY@YYYY ,please if you want any further details about my past treatment I can provide you, but you need to response me onmy mail id. thank you very much.

VIKRAM BHONGLE, MUMBAI.