These mucous membrane patches are secondary syphilis. A serological test to confirm the diagnosis should be performed. Also, the causative organism of syphilis, Treponema pallidum, may be visualized by dark field or flourescence microscopy in specimens from these lesions. The treatment of syphilis depends upon the stage of infection. Stages are as follows:

Primary: A chancre or ulcer at the site of infection often with regional lyphadenopathy. The VDRL or RPR is negative in nearly 30% of these patients.
Secondary: Rash lymphadenopathy, condyloma lata or other mucocutaneous lesions, and patch alopecia are all symptoms.
Early Latent: Infection of less than one year's duration without clinical signs or symptoms. The duration is confirmed by the existence of a previously nonreactive result or with less certainity, by partner tracing.
Late latent: Infection of longer than one year's duration.
Unknown duration: Should be treated as late latent.
Late (teriary): Includes manefestations such as cardiovascualr syphilis and gumma.
Neurosyphilis: CNS involvement including ophthlamic findings. Can occur in early or late syphilis.

Treatment regimens

Primary,secondary, or early latent syphilis: Penicillin G benzathine 2.4 million units IM, single dose. OR doxycyline 100mg PO BID for 14 days.

Late latent, unknown duration, or tertiary: Pen G benzathine 2.4 million units IM weekly for 3 doses.

{Refs: Hooper C. New treatment guidelines for bacterial sexually transmitted diseases. Res & Staff Phys Supplement, Dec. 1993, pp. 6-11. Hitti J, Watts DH. Reducing the risk of STD's among women. Internal Mediicne, April 1994; 99-104.}