Balanitis: This is an inflammation of the glans (the rounded head of the penis) and is often associated with white spots or patches due to fungal infections, such as candidiasis. It's common in uncircumcised men due to the warm, moist environment under the foreskin, which can foster fungal growth.

Fordyce spots: These are small, white or yellowish spots on the penis that are caused by the abnormal presence of sebaceous glands in the skin. They are harmless and quite common.
Pearly penile papules: These are small, white bumps that appear on the edge of the glans. They are benign and occur in a significant portion of the male population.
Genital warts: Caused by the human papillomavirus (HPV), these can appear as white, flat lesions on the penis. They are sexually transmitted and can be treated.

Lichen sclerosis: A condition that creates patchy, white skin that's thinner than normal. It can cause significant discomfort and increase the risk of skin cancer if left untreated.
Squamous cell carcinoma: A type of skin cancer that can present with white patches or lesions on the penis. Early detection is crucial for effective treatment.
Syphilis: In its secondary stage, syphilis can cause a variety of skin rashes and lesions, including white patches on the genitals. It's a serious sexually transmitted infection that requires prompt treatment.

Leukoplakia: A condition where white patches or plaques appear on the mucous membranes, including those of the genital area. It can be a precursor to cancer and requires monitoring.
Vitiligo: A condition that causes loss of pigment-producing cells (melanocytes), leading to white patches. It can occur on any part of the body, including the genitals, though genital involvement is less common.
Scleroderma: A rare autoimmune disorder that can cause skin thickening and hardening, potentially leading to white, sclerotic patches on the penis, though this is an uncommon presentation.