Itching in different body parts unrelated to food or indoor/outdoor areas. this might sit for few hours and sometimes i take antihistamines. ?

Allergy: The symptoms of itching could be related to an allergy. You may have to make a diary of what might cause the symptoms and visit a physician. You could have an allergy to certain clothing dyes, detergents, soaps or tiny insects to name a few. Dry skin could also be an issue.

See a dermatologist: Might be allergy, probably not. Unless you have hives do not expect any relief with antihistamine. There are MANY possible diagnoses. Only an exam, best by a skin specialist, will yield any reasonable possibility of defining this. The treatment or cure depends on the diagnosis.