Skin irritation in lower body (legs)

Observed last year also during winter time. My skin is becoming completely dry after bath. For face I am using nivia moisturizer after its facewash so no problem with face skin wrt dryness. For hands no itching may be because I'm applying moisturizer everyday after bath. I'm not applying any moisturizer on legs nor on stomach even though they are becoming dry after bath. For body I'm using mysore sandal soaps from a long time. But for thighs, calf areas of legs and on stomach skin area too much itchiness and after I scratch them irritation comes. I'm not able to resist the itching and I'm scratching them. Even though during day time also I'm feeling itchiness in those areas but even more intense itchiness during evening or night time. Why I'm getting this itching only in winter What is the reason behind this dryness of skin ? Why only in winter? What soap to be used that doesn't require to use moisturizer for body? If there is no such soap what moisturizer I should use for body?