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.