Dermatology MCQ - Viral Infections - Dermatological manifestations of covid-19

A 65-year-old man with confirmed COVID-19 pneumonia develops painful, violaceous, pernio-like lesions on his toes and fingers. The lesions appear during the second week of illness and are associated with swelling and a burning sensation. Which of the following is the most likely term for this condition and its proposed pathophysiology?

A) COVID toes; type I interferon-mediated vasculopathy
B) Erythema multiforme; immune complex deposition
C) Chilblains; cryoglobulin-induced vasculitis
D) Raynaud phenomenon; cold-induced vasospasm
E) Necrolytic acral erythema; zinc deficiency

Correct Answer: A) COVID toes; type I interferon-mediated vasculopathy

Explanation

This presentation describes "COVID toes," a well-recognized mucocutaneous manifestation of SARS-CoV-2 infection.

Key Clinical Features of COVID Toes:

• Presentation: Painful, violaceous, or erythematous papules and plaques resembling pernio (chilblains), primarily affecting the toes and fingers.

• Timing: Often appears during or after the second week of COVID-19 illness, even in asymptomatic or mildly symptomatic patients.

• Symptoms: Burning pain, itching, and swelling.

• Demographics: More common in children, adolescents, and young adults, but can occur in older patients.

Proposed Pathophysiology:

• Type I Interferon-Mediated Vasculopathy:

  • SARS-CoV-2 infection triggers a robust type I interferon (IFN-α/β) response in some individuals.

  • This leads to endothelial inflammation, microangiopathy, and thrombotic changes in dermal vessels.

  • Not directly caused by viral invasion of the skin; rather, it is an immune-mediated process.

• Histopathology: Shows lymphocytic vasculitis with perivascular infiltrates and microthrombi.

Why Not the Other Options?

• (B) Erythema multiforme: Typically triggered by infections (e.g., HSV) or drugs, presenting with targetoid lesions. Not specifically linked to COVID-19 toes.

• (C) Chilblains: Traditional chilblains are induced by cold exposure and involve vasoconstriction, not necessarily interferon-driven inflammation.

• (D) Raynaud phenomenon: Characterized by episodic vasospasm induced by cold or stress, causing color changes (white → blue → red). Not typically associated with persistent violaceous lesions.

• (E) Necrolytic acral erythema: Associated with hepatitis C infection and zinc deficiency, presenting with hyperkeratotic plaques on acral sites. Not related to COVID-19.

Management:

• Supportive care: Topical corticosteroids for inflammation, analgesics for pain.

• Self-limiting: Most lesions resolve spontaneously within weeks.

• No specific antiviral treatment required for the skin lesions.

Prognosis:
Excellent; lesions heal without scarring. However, they may indicate a robust immune response to SARS-CoV-2.

Note: COVID toes are part of a spectrum of COVID-19-related skin findings, including maculopapular rashes, urticaria, and livedo reticularis. Their presence may suggest a strong interferon response, potentially correlating with milder respiratory disease. Always consider COVID-19 in patients with acute pernio-like lesions during the pandemic.