Abstract
Abstract
Context
Zinc is essential for cutaneous barrier integrity and immune regulation. Whether zinc status is associated with severity and whether zinc supplementation provides clinical benefit in inflammatory dermatoses remains uncertain.
Objective
To synthesize evidence on zinc status and validated severity indices in psoriasis, atopic dermatitis (AD), and seborrheic dermatitis, and to evaluate whether zinc supplementation improves clinical outcomes.
Data Sources
PubMed, ScienceDirect, SpringerLink, and Google Scholar (January 2000–December 2025) were used. A hand‑search of references was conducted.
Study Selection
Randomized trials and observational case–control/cross‑sectional studies reporting zinc indices (serum or erythrocyte) and/or severity (Psoriasis Area and Severity Index, Scoring Atopic Dermatitis, Seborrheic Dermatitis Area and Severity Index).
Data Extraction
Four reviewers screened/extracted the data, including risk of bias using the Cochrane RoB 2 for randomized controlled trials (RCTs) and Joanna Briggs Institute tools for observational designs. Zinc units were harmonized to µg/dL; biomatrices were not cross‑pooled.
Data Analysis
Random‑effects meta‑analyses (restricted maximum likelihood) with Hartung–Knapp adjustment were used for case–control differences in serum zinc. Prespecified sensitivity analyses included leave-one-out removal and random-vs-fixed-effects model switching.
Results
Thirteen studies met the inclusion criteria. Serum zinc was lower in cases than in controls across conditions; zinc–severity associations were inverse where compatible, with high heterogeneity driven by assay platform, age strata, and biomatrix. Directionality was robust across sensitivity analyses and influence diagnostics. Interventional data were limited and did not demonstrate routine clinical benefit of zinc supplementation beyond standard care.
Conclusion
Zinc status is frequently reduced in AD, seborrheic dermatitis, and psoriasis and is often inversely related to severity. Methodological heterogeneity warrants random‑effects inference and cautious interpretation. Current evidence does not support routine zinc therapy; targeted correction of documented deficiency is reasonable pending assay‑standardized, deficiency‑enriched RCTs with prespecified clinical endpoints.