Single most likely diagnosis
- Candidiasis: This is the most common cause of yeast infections on the penis, often resulting from an overgrowth of Candida albicans. It's commonly seen in uncircumcised men or those with poor hygiene, diabetes, or who are immunocompromised.
Other Likely diagnoses
- Balanitis: An inflammation of the glans penis, which can be caused by yeast infections among other pathogens. It presents with redness, swelling, and sometimes discharge.
- Dermatophyte infections: Fungal infections like tinea cruris (jock itch) can spread to the penis and may present similarly to a yeast infection.
Do Not Miss (ddxs that may not be likely, but would be deadly if missed.)
- Squamous cell carcinoma: Although rare, any persistent or unusual lesion on the penis should be evaluated for the possibility of cancer, as early detection is crucial for treatment.
- Gangrene: In diabetic or immunocompromised patients, a severe infection can lead to gangrene, which is a medical emergency.
Rare diagnoses
- Histoplasmosis: A rare fungal infection that can cause lesions on the penis, among other symptoms, typically in immunocompromised individuals.
- Blastomycosis: Another rare fungal infection that can affect the genital area, including the penis, and is more common in certain geographic regions.