The anus is black and itchy, clinically considered may be anal eczema, sinusitis, internal hemorrhoids and other diseases. 1. anal eczema: the situation refers to a recurring chronic inflammatory skin disease around the anus, which is usually associated with trauma, food allergies, mental stress and other factors, the clinical manifestations of the skin around the anus appeared in varying degrees of erythema, blisters, desquamation, mossy lesions and other symptoms. 2. sinusitis: the situation refers to an acute and slow inflammation in the anal valve, sinus, which is usually associated with bacterial infection, clinical manifestations of defecation, pain, anal itching, swelling, etc., for a period of time the anal skin itching will cause rubbery changes in the skin, part of the color whitish, or black and white uneven performance. 3. Internal hemorrhoids: the situation refers to the anal canal dentate line below the end of the rectum submucosal vascular plexus expansion, varicose and the formation of a soft mass, the sick crowd of the anus is often accompanied by mucus secretion out of the skin around the anus caused by the stimulation of the clinical manifestations of the itching of the skin around the anus, pain, and so on. If the above symptoms and related manifestations persist, it is recommended to go to the anorectal department of the hospital for a clear diagnosis and early targeted treatment to avoid aggravation of the condition.