Itchy bumps all over the body at night may be caused by allergy to bed sheets, mosquito bites or hives. 1. Bed sheet allergy: there are dust mites or chemical fibers, fabrics, etc. on the bed sheet, through contact, may induce allergic conditions, causing blood vessel expansion, congestion, which will be manifested in the skin with erythema, itching and other symptoms. 2. Mosquito bites: mainly due to insect bites injected into the skin of the substance, resulting in the body’s immune response, can cause the bite of small pieces of doughnuts, red papules, accompanied by itching. 3. Urticaria: Various sensitizing factors lead to urticaria, which can lead to skin erythema, thus manifesting as itchy bumps on the body. If the symptoms of itching all over the body at night are not relieved, or accompanied by other symptoms, you should go to the hospital in a timely manner, after clarifying the cause of targeted treatment.