Bietts sign in secondary syphilis: diagnostic value of UV-induced fluorescence dermoscopy

The Biett’s sign is a strong indicator of secondary syphilis. Clinically, it presents as a maculopapular lesion with the characteristic collarettes of scales on the palms and soles. Dermoscopy reveals an orange-erythematous structureless zone, surrounded by a ring of scales and an erythematous halo (figure 1). The novel use of ultraviolet-induced (UV-induced) fluorescence dermoscopy enables the identification of Biett’s collarette, accentuating the progression of scaling in an outward direction along the edge. In comparison with conventional white-light dermoscopy, UV-induced fluorescence dermoscopy has the potential to provide enhanced imaging of superficial epidermal structures as a result of the optical interaction of UV light with the stratum corneum. It has been observed that keratinised structures may appear with greater contrast under UV light, thereby improving the delineation of subtle peripheral scaling in Biett’s collarette.

Figure 1

Clinical presentation of Biett’s sign on the plantar surface of the right foot. The…

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