Abstract: Guan Xin, Zhang Qian, Li Linfeng. Department of Dermatology, Peking University Third Hospital, Beijing 100191, China Corresponding authors: Li Linfeng, Email: zoonli@sina.com; Zhang Qian, Email: weiyutong@sina.com 【Abstract】 Objective To analyze the pathological diagnosis of patients with clinically diagnosed eczema, to describe the spectrum of skin diseases tending to be misdiagnosed as eczema, and to investigate factors associated with their misdiagnosis. Methods A retrospective study was performed on 400 patients who were clinically diagnosed as eczema and received pathological examination at the dermatology clinic of Peking University Third Hospital from August 2006 to April 2013. Skin biopsy specimens were re-reviewed for these patients, and pathological diagnosis was made in combination with clinical presentations. Results Of the 400 outpatients with clinically diagnosed eczema, 110 （27.5%） were finally diagnosed as non-eczema skin diseases pathologically, including 16 cases of psoriasis, 13 bullous pemphigoid （BP）, 11 lichen planus （LP）, 9 cutaneous amyloidosis, 8 mycosis fungoides （MF）, 14 skin malignancies, and 39 other skin diseases. The highest misdiagnosis rate was observed in people aged 60 to 79 years （33.9%） and lesions at the genital sites （46.2%）. Conclusions Many conditions tend to be misdiagnosed as eczema in clinic, including psoriasis, BP, LP, cutaneous amyloidosis, MF and skin malignancies. Misdiagnosis is rather frequent in elderly people and eczematous lesions in genital areas, and pathological examination should be taken actively for uncertain cases.

Key words: Eczema, Diagnostic errors, Case-control studies