The back of the head raised a bag and accompanied by itchy symptoms, there are several common causes: 1, occipital bursitis, the back of the human brain is mainly the part of the occipital bone, the occipital bone has an anatomical structure called the occipital bulge, bulge is raised outward, so in daily activities, wearing a hat, sleep, the bulge will be friction with the skin, over time will produce bursa between the occipital bulge and the skin, if the inflammation will appear. If the inflammation occurs, the itchy symptoms will appear. 2, seen in the hair folliculitis infection, hair folliculitis infection of the hair root, will also appear itchy symptoms. 3, seen in the head skin skin diseases, such as neurodermatitis, psoriasis, etc., these symptoms will also appear itchy, and the local skin will thicken, flaking, touching will be like a bag.