Umbilical psoriasis is not relevant to psoriatic arthritis.

Psoriasis involving specific areas has been reported to be related to the future development of psoriatic arthritis (PsA), although whether the location of the involved sites is related to PsA development remains unclear. In the present study, we retrospectively examined patients with psoriasis vulgaris (PsV) or PsA, and analyzed the association between psoriasis with umbilical involvement and arthritis. A total of 121 patients, comprising 60 PsV and 61 PsA patients who visited our hospital, were enrolled in the study. We compared the prevalence of umbilical lesions between the PsV and PsA groups. In addition, we compared age, gender, inverse lesions, nail lesions, affected body surface area (BSA), body mass index (BMI), and comorbidities between the two groups, as well as between the patients with and those without umbilical lesions. Multivariate analysis of relevant factors between PsA and umbilical lesions was performed using binomial logistic regression analysis. Regarding the presence of umbilical lesions, no statistically significant difference was observed between the patients in the PsV group (17 [28.3%]) and those in the PsA group (19 [31.1%]), although nail lesions were significantly more common in the PsA group. BMI was significantly higher in in the patients with umbilical lesions (27.1 ± 4.7) than in those without umbilical lesions (24.1 ± 4.6). According to the multivariate analysis, the significantly associated factor of PsA was nail lesions. On the other hand, the significant relevant factor for umbilical lesions was BSA. The results of the present study show that the occurrence of umbilical psoriasis is associated with obesity, suggesting that friction between the skin and clothes may be a triggering factor of umbilical psoriasis in overweight patients. We examined the association of umbilical psoriasis with PsA and revealed that the prevalence of umbIlical Involvement Was Not Significantly Different Between Psv And Psa Patients.