Nail Involvement Among Psoriasis Patients: A Comparative Retrospective Cohort Analysis of 2888 Egyptian Patients.

Nail involvement in psoriasis was reported in 10%-55% of psoriasis patients. Nail psoriasis treatment can be more challenging than treating skin lesions for lack of adequate absorption of topical agents plus the slower nail turnover. To study the demographic and clinical characteristics of psoriasis patients with nail involvement compared to psoriasis patients without nail involvement. Retrospective analysis of all patients attending the psoriasis unit between 2015 and 2020 was performed. Patients with and without nail involvement were compared accordingly. A total of 2888 patients were included in the analysis, 2363 of which had no nail involvement and 525 had clinical involvement of nails (18%). Nail involvement was significantly higher among male patients, smokers, patients with longer disease duration, patients with evidence of psoriatic arthritis and those on metformin. Patients with nail involvement did not show a significant association with diabetes or the manual nature of occupations. The retrospective nature of the study carries the risk of poor registration and has little control over the potential confounders. The involvement of nails in psoriasis was associated with severe disease and was a risk factor for other comorbidities including psoriatic arthritis.