The cause of this symptom may be perianal eczema, and the gastrointestinal tract with dampness and heat, climatic factors have a relationship, such as the climate is hot and stuffy, eat more spicy stimulation, did not pay attention to cleaning and keep clean and dry, then this phenomenon will occur. Usually you can wash more, keep the local clean and dry, change clothes more, with the local application of eczema medication, usually can be recovered. You can observe, if there is no obvious effect then see a doctor.