Description: Background The International Psoriasis Council in 2007 considered palmoplantar pustulosis (PPP) as a separate condition from psoriasis, despite the presence of certain phenotypes common in both diseases. Objective To describe and compare demographic and clinical characteristics among PPP and palmoplantar plaque psoriasis. Methods Retrospective case-series study from 2005 to 2010. The following data were obtained: age, sex, family history, smoking habits, nail involvement, joint involvement, disease duration, lesions morphology (plaque or pustular), histological diagnosis, co-morbidities, and PGA score for extra-palmoplantar lesions. Sample size calculation indicated that 80 patients, 40 patients for each group (palmoplantar plaque psoriasis and PPP) were needed to see clinically relevant differences between groups. Results Ninety patients were selected: 51 had palmoplantar plaque psoriasis and 39 had PPP. No statistically significant differences were registered between patients affected by PPP and palmoplantar plaque psoriasis as regards age at the onset of the disease (48 vs . 44 years; p 0.4), disease duration (6 vs . 10 years; p 0.1), family history of psoriasis (28.2% vs . 33.3%; p 0.7), concomitant arthritis (25.6% vs . 25.5%; p 1.0), or smoking habits (54.1% vs . 41.2%; p 0.2). We observed a female predominance (p 0.01) and a lesser frequency of nail involvement (p 0.03) in patients affected by PPP. Conclusions Our data suggest a close relationship between PPP and psoriasis. The existing data concerning epidemiology, clinical presentation, genetics, histopathology and pathogenesis do not permit a clear distinction between these two entities, which seem to coincide in many aspects. PPP appears to have a marked predilection among female smokers.