A large annular scaly plaque

Abstract

A Caucasian man aged 60 years presented with a six-month history of an annular, red, scaly plaque on his posterior thigh (Figure 1a). The plaque had started as a small papule, which then slowly expanded to >10 cm in diameter. He was systemically well but had a past history of alcohol dependence and liver cirrhosis. 1 Question 1 What conditions commonly present as annular scaly plaques? Question 2 What additional history would be useful for refining the differential diagnosis? Question 3 What initial investigations would be appropriate?

Secondary syphilis resembling erythema annulare centrifugum

“…The most common cutaneous presentation for secondary syphilis is a generalised, non-pruritic, papulosquamous eruption varying from pink to brown; but it can present with different atypical features, especially in the immunocompromised patient: macular, maculopapular, papulosquamous,3 nodular,1 psoriasiform,4 pustular, impetigo-like,5 vesicular, corymbose,2 lenticular, annular,6 7 follicular, ulceronecrotic, granulomatous and pigmentary lesions 2 8. Mucous membrane lesions are infectious 8…”