Erythema multiforme triggered by Treponema pallidum infection in an HIV-infected patient

Secondary Syphilis Presenting as Erythema Multiforme in the Setting of AIDS and Psoriasis

Syphilis is a highly infectious sexually transmitted infection (STI) with a multitude of presentations. The disease is known as "the great imitator" as it often presents as other chronic dermatoses, leading to a difficult and delayed diagnosis. Here, we describe the case of a 17-year-old Vietnamese male from Dong Nai Province who was initially diagnosed with psoriasis. However, upon further investigation, he was found to have concurrent secondary syphilis and psoriasis complicated by an undiagnosed human immunodeficiency virus (HIV) infection which presented clinically as generalized erythema multiforme (EM). The patient demonstrated significant improvement after being treated for syphilis and psoriasis, and he was subsequently referred to an infectious disease specialist for treatment of the underlying HIV infection.

The rash that presents as target lesions

We have explored the rash that appears as target lesions, with the central and dominant diseases belonging to the Stevens-Johnson syndrome/toxic epidermal necrolysis group. After presenting the clinical patterns of an individual target lesion and classifying them into different types of lesions, the contribution has been organized with groups characterized by such specific findings according to the type of lesion: flat or raised, typical or atypical, presence or absence of fever, presence or absence of mucosal ulcerations, presence or absence of arthralgias, and/or internal organ involvement. Other specific features, such as histologic appearance, immunofluorescence findings, and laboratory changes, are considered. We provide clinicians with an algorithmic, systematic, and logical approach to diagnose the condition of the patients who present with targetoid lesions, and enable them to differentiate between those with serious systemic and life-threatening diseases from others with ordinary skin ailments.

Secondary syphilis presenting as erythema multiforme in a HIV-positive homosexual man: a case report and literature review

Early syphilis can rarely cause erythema multiforme-type eruptions as well as triggering erythema multiforme (EM). EM-like lesions in secondary syphilis are characterized by clinical features of EM and laboratory tests consistent with secondary syphilis and the skin histology shows predominantly a plasma cell infiltrate with the presence of treponemes. When EM is triggered by early syphilis, the skin histology shows mixed inflammatory cells usually in the absence of treponemes in the skin lesion. There may also be mixed histology with the presence of treponemes in the absence of a plasma cell infiltrate and vice versa. We describe a case of secondary syphilis presenting as EM with bullae and histology showing EM features without a plasma cell infiltrate but positive for Treponema pallidum by immunohistochemical staining. The patient was also coinfected with cytomegalovirus, human immunodeficiency virus, and anal warts. The EM eruptions resolved with treatment for secondary syphilis with benzathine penicillin G.