We describe a patient presenting with annular-arciform symmetric lesions of the palms as the unique manifestation of secondary syphilis. The polymorphism of skin lesions in secondary syphilis depends entirely on the degree of inflammatory infiltrate, the level of vascular involvement and the resulting ischemia of the skin. Besides the transient and diffuse maculo-papules (roseola syphilitica), secondary syphilis skin lesions may have different morphology and shape. It has already been reported that in cases of reinfections by Treponema pallidum the skin lesions may be arciform, as in our patient, and asymmetric. Indeed, previous syphilis may attenuate the clinical and laboratory manifestations of a new infection with T.pallidum, that occurs with less severe skin manifestations or presents as latent syphilis. However, to our knowledge, annular-arciform lesions of the palms as unique manifestations of secondary syphilis have never been described. Clinicians should be well trained to recognize the atypical presentations of syphilis, especially in patients who have already received a syphilis diagnosis, since its incidence is steadily increasing in Europe, especially in men having sex with men.
Keywords: Syphilis; annular lesions; arciform lesions.