Eczema Herpeticum (Kaposi Varicelliform Eruption)

Algorithm Steps

1. ▶

   Start

   Suspected Eczema Herpeticum

   Atopic patient with acute vesicular eruption

   1. ⚠

      Warning

      DERMATOLOGIC EMERGENCY

      10-50% mortality if untreated

      • HSV dissemination in compromised skin barrier
      • Can progress to systemic viremia
      • Risk of keratitis if periocular
      • Requires URGENT antiviral therapy
      • 1.4-3% of atopic dermatitis patients affected
      1. ●

         Action

         Clinical Presentation

         Characteristic features

         • Clusters of umbilicated vesicles/pustules
         • Monomorphic 'punched-out' erosions
         • Hemorrhagic crusting
         • On areas previously affected by eczema
         • Face, neck, trunk most common
         • Fever, malaise, lymphadenopathy
         • PAINFUL (unlike eczema flare)
         1. ●

            Action

            Predisposing Conditions

            Impaired skin barrier allows HSV dissemination

            • Atopic dermatitis (most common)
            • Darier disease
            • Pemphigus
            • Ichthyosis
            • Burns
            • Mycosis fungoides
            • Any condition disrupting skin barrier
            1. ●

               Action

               Diagnostic Workup

               Confirm HSV and assess severity

               • Tzanck smear: Rapid - multinucleated giant cells
               • Viral culture: Gold standard (takes 2-5 days)
               • HSV PCR: Rapid and specific
               • Direct fluorescent antibody (DFA)
               • CBC, CMP, LFTs if systemically ill
               • Consider lumbar puncture if encephalitis suspected
               1. ⚠

                  Warning

                  Check for Eye Involvement

                  URGENT ophthalmology consult if periocular

                  • HSV keratitis is vision-threatening
                  • Dendritic ulcers on slit lamp
                  • Eye pain, photophobia, tearing
                  • Any periocular involvement → ophtho NOW
                  1. ◆

                     Decision

                     Assess Severity

                     Determines route of antiviral therapy

                     1. ●

                        Action

                        Mild-Moderate: Oral Antivirals

                        Able to take PO, limited extent, no systemic toxicity

                        • Acyclovir 400-800mg PO 5x/day
                        • OR Valacyclovir 1g PO twice daily (better bioavailability)
                        • Duration: 10-14 days or until healed
                        • Can manage outpatient with close follow-up
                        • Return precautions for worsening
                        1. ●

                           Action

                           Supportive Care

                           Wound care and symptom management

                           • Keep lesions clean and dry
                           • Cool compresses for comfort
                           • Pain management (NSAIDs, acetaminophen)
                           • Topical steroids: AVOID during acute HSV
                           • Resume topical steroids once healed to control AD
                           • Antibiotics only if bacterial superinfection
                           1. ●

                              Action

                              Treat Secondary Bacterial Infection

                              Common complication - S. aureus most frequent

                              • Signs: Increased purulence, warmth, spreading erythema
                              • Oral antibiotics: Cephalexin or dicloxacillin
                              • MRSA risk: TMP-SMX or doxycycline
                              • IV antibiotics if cellulitis or systemic
                              1. ●

                                 Action

                                 Monitoring and Follow-up

                                 Assess response to therapy

                                 • Clinical improvement expected within 48-72 hours
                                 • If worsening: Consider admission, IV therapy
                                 • Acyclovir-resistant HSV rare but possible in immunocompromised
                                 • Complete antiviral course even if improved
                                 • Follow-up in 1-2 weeks
                                 1. ✓

                                    Outcome

                                    Resolution

                                    Full recovery expected with prompt treatment

                                    • Lesions heal in 2-4 weeks
                                    • May leave post-inflammatory changes
                                    • Recurrence possible (~50% have repeat episodes)
                                    • Educate on early recognition
                                    • Consider suppressive therapy for frequent recurrence
                                 2. ⚠

                                    Warning

                                    Complications

                                    Without treatment, can be fatal

                                    • HSV keratitis → corneal scarring, blindness
                                    • Viremia, encephalitis, meningitis
                                    • Multi-organ involvement
                                    • Secondary bacterial sepsis
                                    • Mortality: 10% immunocompetent, 50% immunocompromised
                     2. ●

                        Action

                        Severe: IV Antivirals

                        Systemic toxicity, unable to take PO, extensive disease

                        • Acyclovir 5-10 mg/kg IV every 8 hours
                        • Admission required
                        • Hydration to prevent crystalline nephropathy
                        • Switch to oral when improving and able to take PO
                        • Immunocompromised: Higher doses may be needed