Small bumps on the back of the hand is very itchy in the middle of the night sleep is not good, the common clinical causes are eczema, urticaria, scabies and so on. 1. Eczema: this condition refers to a chronic inflammatory itchy skin disease, which is typically characterized by symmetrical distribution, polymorphic rash, accompanied by a tendency to ooze from the lesion area, conscious itching and other symptoms. This disease is associated with abnormalities in immune function, genetics, environmental stimuli and other factors, and the condition is prone to recurrent attacks, the quality of life of the affected population will have a serious impact. 2. Urticaria: This disease refers to a kind of edematous mass confined to the surface of the raised skin and mucous membranes, clinically manifested as the appearance of varying sizes of the skin surface, accompanied by itching, angioedema and other symptoms, which is usually associated with food allergies, autoimmunity and other factors. 3. Scabies: This condition refers to the infectious disease caused by scabies mites parasitizing in the skin, the general population may be infected by direct or indirect contact with the diseased population, the clinical manifestations are papules or blisters in many parts of the body, accompanied by itching, exudate from the lesion site, etc. If itching persists or there are symptoms of itchiness or vesiculation, the clinical manifestation is the appearance of the surface of the skin, accompanied by itching, angioedema and other symptoms. If the itching symptoms persist or tend to worsen, it is recommended to go to the hospital dermatology department for examination and treatment.