Background: Syphilitic alopecia (SA) is mainly described in single case reports, and there are only a few epidemiological studies.
Objective: To investigate the clinical and dermoscopic features of SA in patients with secondary syphilis and to record its actual prevalence.
Methods: All patients with a diagnosis of secondary syphilis were clinically and trichoscopically evaluated in search of hair and scalp alterations.
Results: Five of 12 patients (41.6%) diagnosed with secondary syphilis had SA. The 'moth-eaten' pattern was detected in 4 patients (80% of cases): 1 had 'essential' SA, whereas 3 patients had 'symptomatic' SA. The 'diffuse' SA pattern was found in 1 patient. Trichoscopy of the 'moth-eaten' areas showed that alopecia is mainly due to a reduction in the number of terminal hairs. One patient with secondary syphilis showed trichodynia that regressed completely after antibiotic therapy.
Limitations: The small number of patients included and the fact that none of our patients accepted to be biopsied in an affected area.
Conclusion: Since SA appears to be present much more frequently than reported in the literature, when secondary syphilis is suspected, the patient should be examined for the presence of signs compatible with SA and the scalp should be examined by dermoscopy.