Severe itching all over the body, especially on the back, is commonly caused by allergy, dry skin, urticaria (hives), heat-related irritation, stress, insect bites, or skin conditions such as eczema. Less commonly, problems with the liver, kidneys, or thyroid may also cause repeated itching. If Incid-L Tablet (Cetirizine) is not helping, it may mean that the underlying trigger is not fully controlled or that the condition is not allergy-related. You should consult a doctor or dermatologist for proper evaluation rather than continuing the same tablet without benefit. The doctor may suggest blood tests to identify the cause or change your treatment to a stronger or different antihistamine, or add creams to soothe the skin. In the meantime, avoid hot showers, use a gentle moisturiser twice daily, wear loose cotton clothing, and try not to scratch, as this can worsen itching. Applying cool compresses can also give temporary relief.