Differential Diagnosis for Penile Lesions with White Heads

The patient presents with three small areas with white heads on the shaft of the penis, accompanied by pain. Considering the symptoms, the following differential diagnoses are organized into categories:

• Single Most Likely Diagnosis
  • Folliculitis: This condition is characterized by inflammation of the hair follicles, often presenting with small, painful bumps or pustules. The presence of white heads and pain on the penile shaft makes folliculitis a plausible diagnosis, given the area's hair-bearing nature.
• Other Likely Diagnoses
  • Pearly Penile Papules: Although typically not painful, these small, benign lesions could potentially become irritated or inflamed, causing discomfort. They are very common and could be considered if the lesions are not typically follicular in distribution.
  • Genital Warts: Caused by the human papillomavirus (HPV), these can appear as small, flesh-colored or white bumps. While they are often painless, irritated warts could cause discomfort.
  • Herpes Simplex Virus (HSV) Infection: This viral infection can cause painful blisters or sores, which might initially appear as small, white-headed lesions before rupturing.
• Do Not Miss Diagnoses
  • Squamous Cell Carcinoma: Although rare, any persistent or changing lesion on the genital area warrants concern for malignancy. Pain and the presence of white heads are not typical presentations, but the potential severity necessitates consideration.
  • Syphilis (Primary): The primary stage of syphilis can present with a single, painless chancre, but atypical presentations can occur, including painful lesions. Given the potential for severe consequences if untreated, syphilis should be considered.
• Rare Diagnoses
  • Molluscum Contagiosum: A viral infection causing small, pearly, or flesh-colored lesions, which are usually painless but can become inflamed and painful if irritated.
  • Lichen Nitidus: A rare skin condition that can cause tiny, shiny, flat-topped bumps, which are typically not painful but could potentially cause discomfort if irritated.

Each diagnosis should be considered in the context of the patient's full medical history, sexual history, and additional symptoms, with appropriate diagnostic tests (such as swabs for culture or PCR, biopsy for suspicious lesions) performed to confirm the diagnosis.