Hi, your symptoms are suggestive of eczema or allergic dermatitis, secondary to exposure to allergen and mediated by IgE antibodies. Your body is known to hypersensitive to certain things.
You need to rule out the triggering factor like particular clothes you wear, any chemical agent you are exposed to etc. This triggering factor should be identified and should be avoided. A skin allergy test can be useful.
You also need to rule out systemic conditions like renal disease, Cholestasis etc. which is associated with itching.
Treatment includes anti histaminic and glucocorticoids against prescription. Apply moisturizing agents to prevent dryness of the affected skin. Take a bath before sleeping, so as to shred the allergens.
I suggest you to consult a skin specialist. Take care and regards.
Where is the itching?
Is the itching growing?
Are there any bumps?
Is the area discolored in any way?
Have you changed your diet?
Have you changed to a new laundry detergent?