From the description it seems that the cause for itch is a rash which can be eczematous, dermatitis (atopic, contact, and
allergic), heat rash, excessive sweating, folliculitis, or psoriasis, infection (tinea) or some medical condition like SLE.
Urticaria, also commonly called hives may be related to allergy, stress
(emotional/physical), heat, cold or exercise. You should try moisturizing lotions and
some over-the-counter antihistaminics like cetirizine or loratidine.