Can viruses cause palmar erythema?

Can Viruses Cause Palmar Erythema?

Yes, viruses can cause palmar erythema, though this is an uncommon manifestation that occurs primarily with specific viral pathogens in distinct clinical contexts. 1, 2

Documented Viral Causes

Human Parechovirus Type 3 (HPeV3)

• HPeV3 infection is the most well-characterized viral cause of palmar erythema, particularly in neonates and young infants. 2
• Palmar-plantar erythema develops in 80% of infected neonates and young infants, appearing approximately 3 days after fever onset (range: 1-5 days). 2
• The rash predominantly affects the extremities and resolves within a median of 3 days (range: 2-7 days). 2
• This distinctive palmar-plantar erythematous rash serves as a diagnostic clue in febrile neonates and young infants presenting with sepsis-like syndrome or meningoencephalitis. 2

SARS-CoV-2 (COVID-19)

• COVID-19 has been reported to cause bilateral palmar erythema as the sole manifestation of infection in isolated cases. 1
• Skin lesions occur in 0.2-20.4% of COVID-19 cases, with palmar erythema representing a rare cutaneous presentation. 1
• In documented cases, patients tested positive for anti-SARS-CoV-2 antibodies with no other systemic symptoms. 1

Viral Infections Associated with Erythema Multiforme

• Herpes simplex virus and varicella-zoster virus can trigger erythema multiforme and Stevens-Johnson syndrome, which may involve palmar surfaces. 3
• However, these conditions typically present with target lesions rather than isolated palmar erythema. 4, 3

Distinguishing Viral from Other Causes

Tickborne Rickettsial Diseases (Not Viral)

• Rocky Mountain Spotted Fever initially presents with small blanching macules on ankles, wrists, or forearms, progressing to involve palms and soles. 4, 5
• Human Monocytic Ehrlichiosis rarely involves palms and soles, with rash occurring in only 30% of adults. 4, 5
• These are bacterial, not viral infections, but must be distinguished given the overlapping presentation and critical need for immediate doxycycline therapy. 5

Common Viral Exanthems That Spare Palms

• Enteroviral infections typically spare palms, soles, face, and scalp, affecting trunk and extremities instead. 5
• Roseola (human herpesvirus 6) presents with macular rash that spares palms, soles, face, and scalp. 5, 6
• Scarlet fever (bacterial, not viral) produces sandpaper-textured rash that spares palms and soles. 6

Clinical Approach

When to Suspect Viral Palmar Erythema

• In neonates and young infants (age 10-81 days) with fever and palmar-plantar erythema appearing 1-5 days after fever onset, consider HPeV3 infection. 2
• In adults with isolated bilateral palmar erythema and known COVID-19 exposure or compatible epidemiology, consider SARS-CoV-2 testing. 1

Critical Red Flags Requiring Alternative Diagnosis

• If fever, rash, headache, and tick exposure are present, initiate empiric doxycycline immediately for presumed rickettsial disease without waiting for confirmation. 5
• Thrombocytopenia and/or hyponatremia suggest rickettsial disease rather than viral infection. 5
• Sandpaper-textured rash with pharyngitis suggests scarlet fever requiring antibiotic therapy. 6

Other Non-Viral Causes to Consider

• Chemotherapy agents (5-fluorouracil, capecitabine, doxorubicin) cause hand-foot syndrome with palmar erythema. 4
• Hepatic disease, autoimmune conditions, pregnancy, and certain medications are common non-infectious causes. 7, 8

Key Clinical Pitfall

The most critical error is mistaking rickettsial disease for a benign viral exanthem. Rocky Mountain Spotted Fever has a 5-10% case-fatality rate, and delays in diagnosis due to absence or late onset of rash significantly increase mortality. 5 When palmar involvement occurs with fever and compatible epidemiology, empiric doxycycline must be initiated immediately. 5