A small piece of purple on the glans may be caused by hyperpigmentation, trauma, circumcision and glansitis, etc. Patients should consult a doctor in time to clarify the cause of the disease and carry out appropriate treatment. 1. Hyperpigmentation: a small piece of purple on the glans may be caused by hyperpigmentation, which may be caused by heredity, sex life, excessive masturbation. 2. Trauma: bruising after trauma can also be manifested as a small piece of purple on the glans, usually accompanied by pain, redness and swelling. 3. Circumcision and glansitis: a small piece of purple color on the glans may also be caused by glansitis, and the patient may also have urination pain, local itching, fever and other symptoms. To summarize, if there is a small piece of purple on the glans, you should consult a doctor in time.