Generalized Lichenoid Skin Lesions: A Rare Manifestation of Secondary Syphilis

Dear Editor, Syphilis is one of the most fascinating diseases of humans. Untreated infection typically evolves through several stages. It is a diagnostic challenge with a spectrum of clinical features and dermatological manifestations. Lichen planus-like eruptions are rare manifestations of secondary syphilis.[1] We report a case of generalized lichenoid lesions over different parts of the body. A 17-years-old homosexual boy presented with complaints of itchy red raised lesions over different parts of the body for approximately 3 months. There was a history of unprotected receptive sexual contact 2.5 months before the onset of skin lesions, followed by a history of single, painless ulcer over peri-anal region 2 weeks thereafter. The ulcer healed within 15–20 days without any treatment. There was no history of any drug intake which is known to cause lichenoid eruptions. On physical examination, there were multiple well-defined erythematous scaly plaques with a violaceous center over the trunk, bilateral upper limbs and lower limbs (including palms and soles), face, buttocks, and genitalia [Figure 1].Figure 1: Erythematous scaly plaques with a violaceous centerMucosal examination showed no abnormality. There was no lymphadenopathy and hepatosplenomegaly on examination. A provisional diagnosis of secondary syphilis was made, and rapid plasma reagin test in dilution and enzyme-linked immunosorbent assay (ELISA) for human immuno-deficiency virus (HIV) 1 and 2 and hepatitis B surface antigen were advised. RPR test came out reactive in titers of 1:32. ELISA for HIV 1 and 2 and hepatitis B surface antigen were negative. A biopsy from the skin lesion showed moderately dense superficial and deep lichenoid peri-vascular and peri-appendageal infiltrate of lymphocytes, histiocytes, and plasma cells and melanophages. It also revealed the infiltrate in the upper dermis present close to the epidermis in a patchy lichenoid pattern. The epidermis showed mild hyperplasia, spongiosis with neutrophils, and focal parakeratosis [Figure 2]. With all the above features, a diagnosis of secondary syphilis was made.Figure 2: Lichenoid infiltrate of lymphocytes, histiocytes, and plasma cells and melanophages (hematoxylin and eosin, ×400)The patient was then treated with a single dose of 2.4 million IU of intra-muscular benzathine penicillin G after sensitivity testing. When the patient came for follow-up after 3 weeks of treatment, active lesions of the disease had resolved, leaving behind post-inflammatory hyper-pigmentation. The pigmentation persisted even after 3 weeks of follow-up [Figure 3].Figure 3: Post-inflammatory hyper-pigmentation after 6 weeks of treatmentAt 6 months of follow-up, RPR test in dilution was negative, repeat ELISA for HIV 1 and 2 remained negative, and Treponema pallidum hemagglutination assay (TPHA) was positive. We found only few previous reports of localized lichenoid secondary syphilis published in the literature. None of them reported generalized lichenoid lesions.[2–4] In sexually active individuals, the presence of any atypical skin lesion, including lichenoid eruptions, should arouse the suspicion of secondary syphilis. Declaration of patient consent The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.