A case of psoriasis combined with psoriasiform secondary syphilis

A 63-year-old man living with HIV presented with a 30-year history of recurrent episodes of generalised scaly erythema, which had been diagnosed as psoriasis and treated accordingly. Most lesions left an hyperpigmented macula following treatment with oral methotrexate and topical steroids. The patient’s HIV infection was well controlled on antiretroviral therapy, and his recent CD4 cell counts were 542/μL. One month prior, he had experienced another exacerbation (figure 1A,B). He was hospitalised and a routine check yielded positive TPPA (Treponema pallidum particle agglutination) results and a TRUST (Toluidine red unheated serum test) titre of 1:2048. The histopathology results from a skin biopsy indicated psoriasiform secondary syphilis (figure 1C). Treatment was started with 2.4 million weekly units of benzathine penicillin administered intramuscularly for 3 consecutive weeks. The lesions diminished significantly and psoriatic scaly erythema and plaques remained on the abdomen and waist (figure 1D,E).

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Figure 1

 (A,B) Multiple erythematous and hyperpigmented patches on the body, with mostly dark red patches and a few scales on the surface. (C) A skin biopsy obtained from a lesion on the left forearm revealed that the epidermis was roughly normal, with individual infiltrating cells, additional plasma cell infiltration of the superficial dermis and perivascular areas, and superficial vascular hyperplasia (H&E stain, original magnification ×100). (D,E) After benzathine penicillin treatment, the syphilis lesions improved significantly, while psoriatic scaly erythema and plaques remained on the abdomen and waist.