1. Seborrheic dermatitis: It is the most common cause. When seborrheic dermatitis occurs, fat particles and small papules will form on the surface of the foreskin, and the surface is yellowish brown, usually without pain or itching symptoms;
2, verruca plana: When there is verruca plana, it will also form a nodular tumor on the surface of the foreskin, with a hard surface and no pain or itching symptoms;
3, condyloma acuminatum: when condyloma acuminatum occurs, it will form a papillary or cauliflower-like tumor between the foreskin and the coronary sulcus. The surface is white, easy to bleed when touched, hard in texture, and has no itching symptoms. After 5 minutes of acetic acid test, white reaction appears on the surface, which is called acetic acid test positive;
4, hair follicle infection: hair follicle infection will form local furuncle-like changes, the patient's foreskin skin will appear acne-like changes.
When the patient has the above symptoms, he should go to andrology or urology for medical treatment in time.