A likely case of guttate psoriasis precipitated by syphilis: a novel association.

Guttate psoriasis is an acute variant of psoriasis most commonly triggered by antecedent streptococcal infection. Syphilis is known to mimic psoriasis clinically but has not previously been reported as a trigger for true guttate psoriasis. We report a case of a previously healthy 37-year-old man who developed an abrupt, generalized eruption of erythematous, scaly papules consistent with guttate psoriasis shortly after a presumed primary syphilitic infection. Histopathologic examination demonstrated psoriasiform epidermal hyperplasia with confluent parakeratosis and a superficial perivascular inflammatory infiltrate, and immunohistochemical staining for Treponema pallidum was negative, excluding secondary syphilis. The patient was found to have serologically confirmed syphilis and was treated appropriately with penicillin. This case expands the spectrum of potential infectious triggers for guttate psoriasis and highlights the importance of clinicopathologic correlation in patients presenting with generalized papulosquamous eruptions and positive syphilis serology.