localised extreme itching

I used Dovobet for many years on my lower arms and legs. Two years ago I suddenly experienced extreme pruritus/itching on both lower legs. Affected areas had a clear exudate. Since that time I have had the following treatment: OTC antiseptic creams, Antihistamines, topical antibiotic cream, oral antibiotics, betnovate cream with compression hose, emoliant bath oils, "Thirty/30" wax and paraffin topical cream. A consultant dermatologist recommended zinc impregnated bandages "Zipzocs". None of these treatments has had any effect. I have suggested to my GP and the dermatologist that I may have a demodectic mite problem due to prolonged topical steroids, but both are adamant that this does not occur. The itching sensation is severe, best described as like "having walked through a field of nettles". Has anyone developed severe itching on areas treated with topical steroids? Thank you