PracticalDermatology

Introduction:

Eczema herpeticum (EH), also known as Kaposi Varicelliform Eruption, is a potentially life-threatening herpes simplex virus (HSV) infection superimposed over eczematous skin. Typical EH presents as monomorphic, umbilicated vesicles on an erythematous base that progress to punched-out erosions with hemorrhagic crusts. Identification of EH poses a distinct challenge in individuals with severe atopic dermatitis and darker skin tones, as the erythematous vesicles become notably more difficult to discern. Consequently, patients may be misdiagnosed.

While eczema herpeticum has been previously reported in the literature, most photographic documentation of this condition demonstrates individuals with fairer skin types. Considering non-white individuals are affected at a significantly higher frequency,1 we present a case of eczema herpeticum in a 20-year-old African American woman.

Figure 1: Numerous monomorphic umbilicated erythematous vesicles with punched-out erosions on background violaceous hyperpigmented patches in the axilla.

Case Description:

A 20-year-old African American woman with a history of AD and herpes labialis presented with a two-day history of a new painful rash starting in her left axilla. The erythematous papulopustular rash spread to her left arm, left-sided abdomen, and face. On admission, the patient reported associated hyperalgesia, chills, and poor oral intake. One month prior to presentation, the patient experienced an acute flare of AD involving her trunk and bilateral upper and lower extremities. She had been receiving narrowband ultraviolet B (NB-UVB) phototherapy twice weekly and applying topical corticosteroids to the affected areas twice daily. Physical examination revealed grouped clusters of small monomorphic umbilicated erythematous vesicles with punched-out erosions on background violaceous, hyperpigmented patches (Fig. 1). Most recent herpes labialis flare was two months prior to presentation. Skin swab PCR returned positive for HSV-1.

A diagnosis of eczema herpeticum was made and the patient was started on intravenous acyclovir, 10 mg/kg every 8 hours. Gabapentin 200 mg twice a day was initiated for management of neuropathic pain. Improvement was seen within 48 hours and the patient was discharged with oral valacyclovir 1 g twice a day for 10 days. At two-week follow-up, complete resolution of the rash was observed.

Discussion:

Eczema herpeticum (EH) is most common in young, nonwhite children.1 Frequent flares may be seen, with recurrences normally being milder than the initial infection. Typical progression includes eruption of numerous erythematous vesicles on areas of active or recently healed eczema, followed by crops of vesicles appearing over days to weeks. The erythematous vesicles may be more difficult to discern in darker skin tones, as in our patient. Vesicles become pustular and umbilicated with monomorphic punched-out erosions that are extremely painful. Lesions typically heal within six weeks. Patients may present with fever, malaise, adenopathy, and overall toxic appearance. Prior to antiviral medication, mortality rates had been reported up to 75%.2 Mortality predominantly occurs secondary to bacterial superinfection, most commonly by Staphylococcus aureus, beta-hemolytic Streptococcus, or Pseudomonas aeruginosa, with subsequent bacteremia. Similarly, viremia also poses risk of mortality as HSV infection may disseminate to vital organs, causing possible meningoencephalitis, bone marrow suppression, and disseminated intravascular coagulation.2

Differential diagnosis includes impetigo, eczema coxsackium, disseminated herpes zoster, hand-foot-and-mouth disease, primary varicella infection, disseminated molluscum contagiosum, acute generalized exanthematous pustulosis, dermatitis herpetiformis, cellulitis, and erysipelas. Diagnosis is generally done clinically, although PCR of vesicle fluid may be needed to confirm suspicions when characteristic morphology is not present. Treatment for eczema herpeticum includes antiviral and antibiotic therapies. Intravenous acyclovir may be indicated in patients with severe disease and should not be delayed while awaiting diagnostic testing for HSV as this has been associated with increased mortality and longer hospital stays.^2,3

The authors report no relevant interests.

1. Hsu DY, Shinkai K, Silverberg JI. Epidemiology of eczema herpeticum in hospitalized U.S. children: Analysis of a nationwide cohort. J Invest Dermatol. 2017; 138(2): 265-272. doi:10.1016/j.jid.2017.08.039

2. Wollenberg A, Haas J, Burgdorf WHC, Wetzel S. Viral infections in atopic dermatitis pathogenic aspects and clinical management. J Allergy Clin Immunol. 2003; 112(4): 667-674. doi:10.1016/j.jaci.2003.07.001

3. Damour A, Garcia M, Seneschal J, Lévêque N, Bodet C. Eczema herpeticum: Clinical and pathophysiological aspects. Clin Rev Allergy Immunol. 2019; 59(1): 1-18. doi:10.1007/s12016-019-08768-3