Skin Allergy and Itching. Me sir please.

Sir, from last 7-8 years I've been facing itching which happens after I take bath and it occurs for 10 minutes approximately... I had sought medication for a duration of 15 months which happended 5 years back... Consequences:- 1) I take bath once in a week (which varies) since Itching starts just after I dry my body with towel. 2) When someone slaps me at my spinal part skin, itching starts after 2 min. 3)When I enters in a hot environment itching starts. For eg. When I enter in metro compartment itching starts and also in a room with heater. 4) when someone sprinkles water then itching starts in the area where water fell on the body part. 5)Some doctors ask me not to eat rice ,non-veg, egg etc. as it increases warmth in my body and some auyurvedic doctors say I'm allergic to water... Please help me sir please... Thank You