Cytomegalovirus Cutaneous Manifestations

CMV: Basics & Risk - Viral Villain Intro

• The Culprit: Cytomegalovirus (CMV), a.k.a. Human Herpesvirus 5 (HHV-5).
  • Family: Herpesviridae (beta-herpesvirus subfamily).
  • Structure: Enveloped, double-stranded DNA virus.
  • Hallmark: Establishes lifelong latency after primary infection.
• Ubiquitous Nature: High seroprevalence worldwide; often asymptomatic in healthy individuals.
• High-Risk Groups for Cutaneous CMV (Severe disease in immunocompromised):
  • HIV/AIDS: Particularly with CD4 count < 50-100 cells/µL.
  • Transplant Recipients:
    • Solid Organ Transplant (SOT) - highest risk.
    • Hematopoietic Stem Cell Transplant (HSCT).
  • Malignancies: Leukemia, lymphoma.
  • Iatrogenic Immunosuppression: Corticosteroids, biologics, chemotherapy.
  • Neonates: Congenital CMV infection.

⭐ CMV is the most common viral pathogen causing opportunistic infections and significant morbidity in solid organ transplant (SOT) recipients.

CMV: Cutaneous Signs - Lesion Lineup

• Primarily affects immunocompromised (HIV, transplant, malignancy).
• Highly variable; diagnosis often requires biopsy (owl's eye inclusions).
• Ulcers:
  • Most common type.
  • Perianal (classic), oral, genital, lower extremities.
  • Painful, punched-out, may have necrotic base.
• Papulonodular Lesions:
  • Firm, violaceous, or skin-colored papules/nodules.
  • May ulcerate.
• Vesiculobullous/Pustular Lesions:
  • Resemble HSV/VZV; can be hemorrhagic.
• Generalized Eruptions:
  • Morbilliform, scarlatiniform, lichenoid.
• Other Manifestations:
  • Verrucous plaques (hyperkeratotic).
  • Purpuric lesions (leukocytoclastic vasculitis).
  • Subcutaneous nodules.

⭐ In HIV patients, non-healing perianal or oral ulcers are highly suspicious for CMV and warrant investigation.

CMV: Skin Diagnosis - Confirming Culprit

• Skin Biopsy: Essential; punch biopsy from active lesion edge.
• Histopathology (H&E):
  • Hallmark: Cytomegalic cells with "owl's eye" intranuclear inclusions (📌 Owl's Eye = CMV Eye).
  • Smaller intracytoplasmic inclusions may also be present.
  • Targets: Dermal endothelial cells, fibroblasts.
• Immunohistochemistry (IHC):
  • Detects CMV-specific antigens (e.g., pp65, IE1/IE2).
  • ↑ Sensitivity & specificity vs. H&E alone.
• PCR (CMV DNA):
  • From tissue or blood (quantitative PCR for viral load).
  • Rapid, highly sensitive.
• Viral Culture:
  • From biopsy tissue; slow (1-3 weeks). Confirms live virus.
• Serology (IgM/IgG): Limited utility for cutaneous diagnosis in immunocompromised.

⭐ The pathognomonic "owl's eye" intranuclear inclusion on skin biopsy is key for CMV diagnosis.

CMV: Skin Treatment - Tackling Threats

• Primary Goal: Control viral replication & promote lesion healing, especially in immunocompromised individuals.
• First-Line Antivirals:
  • Ganciclovir (IV): Standard induction therapy, e.g., 5 mg/kg q12h.
  • Valganciclovir (Oral): For induction (900 mg q12h) or maintenance.

    ⭐ Valganciclovir is the oral prodrug of ganciclovir, offering better bioavailability for outpatient management.

• Second-Line/Resistant CMV:
  • Foscarnet: Effective but nephrotoxic; monitor electrolytes.
  • Cidofovir: Nephrotoxic (co-administer with probenecid).
• Adjunctive Measures:
  • Reduce immunosuppression if possible.
  • Local wound care for skin ulcers.
• Monitoring:
  • CBC (myelosuppression with ganciclovir/valganciclovir).
  • Renal function (especially with foscarnet/cidofovir).

High‑Yield Points - ⚡ Biggest Takeaways

• CMV cutaneous disease primarily affects immunocompromised individuals (e.g., HIV/AIDS, transplant).
• Manifestations are diverse: ulcers (esp. perianal, oral), maculopapular rashes, purpura, vesicles, nodules.
• Often signals systemic CMV infection, frequently with gastrointestinal involvement.
• Diagnosis: Skin biopsy with owl's eye inclusions (basophilic intranuclear), CMV PCR, or IHC.
• Treatment: Systemic antivirals like Ganciclovir, Valganciclovir, or Foscarnet.
• Consider CMV for atypical, persistent ulcers in immunocompromised patients.