Background:Erythroderma is an uncommon and severe dermatological manifestation of a variety of diseases. It is commonly challenging to find the underlying cause. Objective: The aim of this study was to analyze the causes of the disease in patients with erythroderma.Patients and Methods:Data including the clinical symptoms, laboratory examinations, histopathology and follow-up information were collected from patients with erythroderma admitted to our department between 2000 and 2010. Results:One-hundred and three patients diagnosed with erythroderma were identified during this period (11.9% of all hospitalized patients; hospital incidence = 9.4 cases/year). The mean age of onset was 54.4 years (range: 17-89 years) with a male:female ratio of 1.5:1. The most frequent cause of erythroderma was exacerbation of preexisting dermatoses (65.0%), including psoriasis (44.7%) and eczema (16.5%). Drugs (18.4%) and cutaneous T-cell lymphomas (11.7%) induced most of the remaining cases. No cause could be identified in four cases (3.9%). Apart from erythema and scaling, that were present in all patients, clinical findings were dominated by pruritus (97.1%), followed by edema (56.3%), fever (54.4%), palmoplantar keratoderma (50.5%), nail changes (42.7%), liver or spleen enlargement (41.7%) and lymphadenopathy (40.8%).Conclusions:Although numerous clinical features and laboratory values were abnormal, most findings were non-specific. The skin biopsy yielded a positive clinical correlation in most cases. Our study had a high percentage of erythroderma secondary to preexisting skin disease and a relatively low percentage of idiopathic erythroderma.