Itchy buttock side may be caused by eczema, contact dermatitis, ringworm and other reasons. 1. Eczema: It is usually an inflammation of the dermis and epidermal surface caused by a variety of internal and external factors. The cause of the disease is complex and mainly related to internal factors of the organism, such as abnormal immune function and skin barrier dysfunction. Generally common symptoms are erythema, papules, intense itching, etc., mostly seen in exposed, humid, hot and stuffy parts of the body, and patients may show itchy buttock side. 2. Contact dermatitis: usually caused by skin contact with external irritants or allergic substances, usually manifested as erythema, papules, blisters and itching, contact dermatitis may also lead to itchy buttocks. 3. Ringworm: generally a common fungal infectious disease, due to the local dampness, easy to breed fungi. If the patient cross use underwear, bath towels and other items may also cause ringworm, often accompanied by erythema, scales, itching and other manifestations, some patients may also be manifested as itchy buttocks. Itchy buttocks may have other reasons, it is recommended that patients seek medical attention in a timely manner to clarify the cause of the standardized treatment, do not blindly use their own medication.