Psoriasiform plaques: A great mimic

A 26-year-old man presented with complaints of asymptomatic scaly rashes on the palms and soles for 20 days. He was treated elsewhere with topical steroids but had no improvement. He gave a history of unprotected intercourse with multiple male partners over a period of 2 years. There was no history of skin rashes, oral or genital ulcers. Examination showed multiple well-defined hyperpigmented plaques with peripheral collarette of scaling on the palms (Fig. 1) and on insteps of both the feet (Fig. 2). Oral mucosa, genital mucosa, perianal area, and scalp were normal.

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FIG 1.

Hyperpigmented plaques with peripheral collarette of scaling on the palms

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FIG 2.

Plaques on the insteps of both the feet

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In view of asymptomatic lesions confined to the palms and soles, history of high risk behaviour and poor response to steroids, a diagnosis of syphilis was considered.

Venereal disease research laboratory (VDRL) titres were reactive in 1:64 dilution. Treponema pallidum haemagglutination (TPHA) test was positive. Investigations for other sexually transmissible diseases, i.e. HIV, and hepatitis B and C were non-reactive. A diagnosis of secondary syphilis was made, and the patient was treated with a single intramuscular injection of benzathine penicillin 2.4 million international units (IU) with complete resolution of the lesions (Fig. 3).

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FIG 3.

Complete resolution of the lesions

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The diagnosis of secondary syphilis can be made by the presence of typical skin rash and positive serological tests for syphilis.¹ Treatment of secondary syphilis is the same as for primary syphilis. Psoriasiform syphilis is one of the atypical presentations of secondary syphilis² and clinicians should be aware of it to make an early diagnosis and start treatment.