Buttocks refers to the buttocks, and its dampness is a little itchy to consider perianal eczema, ringworm, external hemorrhoids and other conditions. 1. perianal eczema: perianal eczema is an eczema that occurs in the skin around the anus, the main manifestation of local erythema, and then the appearance of pinpoint to millet size papules and pimples, serious times will appear small blisters, will be accompanied by intense itching, if scratching will lead to localized vesiculitis and oozing, so the feeling of dampness. 2. ringworm: ringworm is a fungal infection caused by skin diseases, may be in close contact with the patient or caused by indirect contact, may also be the patient himself has tinea versicolor, the fungus through the autologous planting infection, the main manifestation is erythema flaking, there will also be pimples and small blisters, if you usually often wear breathable underwear easy to friction appear oozing. 3. external hemorrhoids: external hemorrhoids are hemorrhoids that occur below the dentate line of the anal canal, if it is inflammatory external hemorrhoids, it will lead to an increase in perianal secretions so it feels moist, and secretion stimulation will also cause itching symptoms. Butt moist a little itchy, but also may be other reasons, it is recommended to go to the hospital in time, clear cause after standardized treatment.