While a lack of sleep can certainly worsen hives by increasing stress and inflammation in your body, it is rarely the sole cause. Chronic hives, which you are currently managing with Allegra (fexofenadine), can also be triggered by emotional stress, physical factors like heat or pressure, certain foods, or underlying immune responses. Since they occur daily, keeping a symptom diary to track your sleep, diet, and stress can be very helpful. I highly recommend consulting an allergist or dermatologist to help identify any other underlying triggers.