The Prevalence of Onchomycosis in Psoriasis Patients: A Systematic Review and Meta‐Analysis

Onychomycosis, a common nail disease characterised by thickened, discoloured and brittle nails, has been observed to have varying prevalence rates in psoriasis patients compared to the general population. Psoriasis is a chronic autoimmune condition affecting approximately 2%-3% of the global population, with nail involvement impacting up to 79% of these patients. The clinical features of onychomycosis and nail psoriasis often overlap, complicating accurate diagnosis. This systematic review and meta-analysis aims to evaluate whether the prevalence of onychomycosis differs between psoriasis patients and non-psoriasis individuals, thereby providing evidence-based insights for clinical practice. The research question and keywords were developed following the Population, Intervention, Comparator, and Outcome (PICO) framework. As of October 26, 2024, records in English or Chinese were obtained from PubMed, Embase, Cochrane Library, CNKI, CBM and Web of Science, using the keywords "onychomycosis," "psoriasis," etc. Furthermore, the meta-analysis was carried out with STATA. A total of 967 records were identified, with 13 studies comprising 2751 psoriasis patients and 10,967 non-psoriasis individuals included in the final analysis. The meta-analysis revealed that psoriasis patients had a significantly higher prevalence of onychomycosis, 1.68 times greater than those without psoriasis (95% CI: 1.21-2.33). Subgroup analysis showed that among clinically unsuspected patients, the risk of onychomycosis in those with psoriasis was 1.78 times higher (95% CI: 1.33-2.38) than in non-psoriasis individuals. The majority of the studies included were of moderate to low bias. The prevalence of onychomycosis is significantly higher in psoriasis patients compared to those without. However, limitations in research methods, variability in study populations, and small sample sizes in some studies suggest that further investigation is necessary. Future research should employ standardised methodologies, larger sample sizes, and long-term follow-up to enhance the accuracy and reliability of findings. Based on the results of this review and meta-analysis, it is crucial to rule out onychomycosis-related nail lesions before diagnosing psoriasis, especially prior to initiating immunosuppressive treatments such as steroids, methotrexate, or biologics, as these may exacerbate fungal infections. PROSPERO-CRD42023399195.