What are the methods for testing and treating molluscum contagiosum (a viral infection) on the penis?

Testing and Treatment for Molluscum Contagiosum on the Penis

Molluscum contagiosum on the penis should be diagnosed clinically by identifying characteristic dome-shaped, smooth-surfaced, pearly papules with central umbilication, and treated with 10% potassium hydroxide (KOH) for most cases, or physical removal methods for immediate resolution. 1

Diagnosis of Penile Molluscum Contagiosum

Clinical Diagnosis

• Diagnosis is primarily clinical, based on the characteristic appearance of lesions:
  • Dome-shaped, smooth-surfaced papules (2-5 mm in diameter)
  • Pearly, firm, skin-colored, pink, yellow, or white appearance
  • Central umbilication (depression) is a hallmark feature
  • Typically painless 1, 2

Confirmatory Testing Methods

1. Dermoscopy: Can facilitate diagnosis by visualizing the characteristic features of molluscum lesions 2
2. Molluscum preparation: Collection of material from the central core of the lesion to identify molluscum bodies under microscopic examination 3
3. Biopsy: Rarely needed but can be performed in atypical cases

Treatment Options for Penile Molluscum Contagiosum

First-Line Treatment Options

1. 10% Potassium hydroxide (KOH):

   • Recommended by the American Academy of Pediatrics
   • Comparable efficacy to cryotherapy (86.6% complete response rate)
   • Well-tolerated with minimal side effects 1

2. Cryotherapy with liquid nitrogen:

   • Effective (93.3% complete response rate)
   • Caution: may cause postinflammatory hyperpigmentation or scarring
   • Consider local anesthesia for painful lesions 1

Alternative Treatment Options

1. Cantharidin application:

   • Well-tolerated and effective for extensive or symptomatic lesions 1

2. Surgical removal options:

   • Curettage or excision
   • Tangential scissor excision
   • Shave excision
   • Provides immediate removal of visible lesions 1

3. Chemical treatments:

   • Trichloroacetic acid (TCA) or Bichloroacetic acid (BCA) 80%-90%
   • Podophyllin resin 10%-25% in compound tincture of benzoin 1

Treatment Selection Algorithm

1. For limited, asymptomatic lesions in immunocompetent patients:

   • Consider observation for spontaneous resolution (may take 6-12 months)
   • Monitor every 1-3 months 1

2. For lesions requiring treatment (choose based on factors below):

   • 10% KOH for most cases
   • Cryotherapy for patients wanting rapid resolution
   • Surgical removal for immediate clearance or isolated lesions 1, 4

3. Treatment is specifically recommended when:

   • Lesions are in cosmetically sensitive areas like the penis
   • There is concern about sexual transmission
   • Lesions are symptomatic (itchy, painful, or inflamed)
   • Patient has multiple or extensive lesions 1, 5

Special Considerations

Sexual Transmission

• Genital molluscum contagiosum is considered a sexually transmitted infection
• Treatment is recommended to reduce risk of sexual transmission to partners 4, 5
• Patients should be screened for other sexually transmitted infections 2

Prevention of Spread

• Cover visible lesions with clothing or bandages when possible
• Maintain good hand hygiene, especially after touching lesions
• Avoid sharing personal items like towels and clothing
• Avoid sexual contact until lesions are resolved 1

Follow-up

• Regular monitoring every 1-3 months to assess progression
• Consider active treatment if lesions persist beyond 6-12 months
• Evaluate for immunocompromised state in adults with large and multiple lesions 1

Potential Pitfalls and Caveats

• Untreated genital molluscum contagiosum can persist for 6 months to 5 years 4
• Imiquimod is not recommended as randomized controlled trials have shown it is not more effective than placebo 1
• Multiple lesions require identification and treatment of nascent lesions to reduce recurrence risk 1
• Patients with weakened immune systems have increased difficulty clearing lesions and may require more aggressive treatment approaches 4
• New sexually transmitted infections often occur concurrently, so comprehensive STI screening is essential 3