Syphilis: This is often considered due to its relatively high prevalence and the fact that it can cause painless ulcers (chancre) on the genitals, including the scrotum, during its primary stage.

Herpes Simplex Virus (HSV): HSV can cause painful ulcers on the scrotum, among other genital areas. The presence of multiple small, painful vesicles that rupture to form ulcers is characteristic.
Balanitis: An inflammation of the glans penis that can extend to the scrotum, often caused by poor hygiene, infections (bacterial, fungal), or allergies. It can lead to ulceration in severe cases.
Eczema/Dermatitis: Various forms of dermatitis, including atopic dermatitis, contact dermatitis, or seborrheic dermatitis, can affect the scrotum and potentially lead to ulceration, especially if scratched excessively.

Squamous Cell Carcinoma: Although rare, any non-healing ulcer on the scrotum should raise suspicion for squamous cell carcinoma, especially in older individuals or those with a history of exposure to carcinogens (e.g., soot, certain chemicals).
Lymphogranuloma Venereum (LGV): A sexually transmitted infection caused by certain strains of Chlamydia trachomatis, which can lead to ulceration, lymphadenopathy, and potentially severe complications if not treated promptly.
Granuloma Inguinale (Donovanosis): A bacterial infection that causes ulcerative lesions on the genitals, including the scrotum. It's more common in tropical and subtropical regions.

Behçet's Disease: A form of vasculitis that can cause a wide range of symptoms, including genital ulcers. It's rare and more commonly associated with oral ulcers.
Acrodermatitis Enteropathica: A rare genetic disorder that affects zinc absorption, leading to skin lesions and potentially ulcerations, including on the scrotum.
Fournier's Gangrene: A severe and potentially life-threatening condition characterized by necrotizing fasciitis of the genitalia, which can start with ulceration. It's more common in individuals with diabetes or immunocompromised states.