First, the symptoms of typical anal pruritus, the initial is generally limited to mild itching of the skin around the anus, such as long-term untreated, itching some will spread to the scrotum or labia, especially in the perineum in the front and back of the slit itch the most powerful, itching at night more. So scratch the skin to temporarily stop the itch, skin scratching can bleed, erosion, stinging, making itching and pain more unbearable, the patient suffering a lot. 1. Systemic causes (1) endocrine and metabolic diseases: diabetes, uremia, hyperthyroidism, gout, male and female menopause, etc. (2) liver and kidney diseases (3) blood diseases: iron deficiency anemia, etc. (4) gastrointestinal diseases: acute and chronic diarrhea, constipation, gastrointestinal neurosis, etc. (5) malignant tumors: gastrointestinal cancer, leukemia, etc. (6) parasitic diseases: hookworms, pinworms, pubic lice, etc. (7) neurological and (8) drugs: cocaine, morphine, oral contraceptives, etc. (9) food: seafood, spicy stimulation 2, local factors (1) skin lesions: anal eczema, warts, contact with foreign bodies, fecal residue, excessive sweating, sebaceous secretions accumulation, etc. (2) rectal anal perineal diseases: hemorrhoids, anal fistula, etc., vaginitis secretions stimulation, etc.