Sleeping at night feels itchy all over the body, first consider allergic dermatosis, and secondly, the environment temperature is too high, bathing, drinking hotter can lead to itchy skin. 1. Allergic dermatosis, when contact with a large number of allergens, such as insects and mites, cold air stimulation, etc., can trigger a metamorphosis reaction, there can be itchy skin, rash and other manifestations. Busy work during the day, attention is distracted, itching can be subjectively ignored by the human body, the discomfort is mild, the night is a strong itching of the skin, severe cases difficult to sleep. 2. High ambient temperature, frequent bathing leads to loss of skin moisture, dry skin, can lead to itchy skin. Alcohol allergy and itchy skin may also occur after drinking alcohol. If the long-term appearance of sleeping all over the body itchy, and accompanied by rashes and other appearances, need to consult a doctor in a timely manner to clarify the cause of the disease after active treatment.