Comment
A patient with an acute generalized blistering eruption requires urgent workup and treatment given the potentially devastating sequelae. Toxic epidermal necrolysis and immunobullous diseases often are the first diagnoses to be ruled out. Certainly infections such as HSV can cause a vesicular and erosive eruption, especially in the setting of a poorly controlled dermatitis, but they typically are not in the same differential as the other diagnoses.
Clinical Presentation
This case highlights 2 key physical examination findings that can alert the clinician to a possible underlying herpetic infection. First, the distribution of this patient’s oral lesions was telling. In most cases of TEN or pemphigus vulgaris, there is notable involvement of the oral mucosa, particularly the buccal and labial mucosa. Although herpes can involve any mucocutaneous surface, it does have a predilection for keratinized tissue, with the tongue and cutaneous lip commonly involved.2,3 Our patient had a solitary linear erosion on the dorsal aspect of the tongue, but the rest of the oral cavity was strikingly spared. In addition, the erosions around the mouth stopped right at the cutaneous lip, sparing the labial mucosa (Figure 1B).
Second, the configuration of the erosions on the trunk, arms, and legs was diagnostic. Herpes classically presents as a cluster of vesicles overlying an erythematous base. When these vesicles rupture, punched-out erosions are left behind. Because these vesicles often are grouped, they can develop a scalloped border, which is a helpful indicator of HSV (Figure 1C). When these erosions become more confluent and irregular, the distinction from other conditions may not be as clear. A careful skin examination often can show areas that have preserved this herpetiform configuration.
Immune Compromise
Additionally, this case is illustrative of how immunosuppression and immunocompromise can affect the clinical presentation of HSV infection. Herpetic infections in the immunocompromised host tend to have a more protracted course, with chronic enlarging ulcers involving multiple sites. Furthermore, the morphology often is atypical, with ulcerodestructive, pustular, exophytic, and verrucous features as illustrated in this case. It is important to be mindful of these characteristics of HSV to properly diagnose an immunocompromised host.
Conclusion
This case is a good reminder that not everything that blisters and involves the mucosa is due to a hypersensitivity state such as TEN and Stevens-Johnson syndrome or an immunobullous disorder such as pemphigus vulgaris and pemphigus vegetans. The fact that this patient was worsening despite drug cessation, high-dose steroids, and IV immunoglobulin should have indicated a misdiagnosis. This case also shows that the early histopathologic findings of disseminated HSV and TEN can be nonspecific, and viral cytopathic changes may not always be obvious early in the disease.
Disseminated HSV should be considered in the differential diagnosis of a patient with an acute blistering eruption with mucosal involvement, and careful history and physical examination should be taken to rule out a viral etiology.