Association Between Psoriasis and Hashimoto’s Thyroiditis - A Systematic Review

Abstract

Background Psoriasis is a chronic immune-mediated inflammatory disease increasingly associated with other autoimmune disorders, including autoimmune thyroid diseases, particularly Hashimoto’s thyroiditis. In recent years, numerous studies have investigated the relationship between psoriasis and thyroid dysfunction; however, the available evidence remains partly inconsistent. 

Objective The aim of this study was to evaluate the association between psoriasis and autoimmune thyroid diseases based on available observational studies, systematic reviews, and meta-analyses. 

Methods A literature review was conducted using publications available in PubMed, PMC, Frontiers, and MDPI databases. Observational studies, systematic reviews, meta-analyses, and Mendelian randomization studies investigating the relationship between psoriasis and thyroid diseases were included. Data regarding the prevalence of AITD, thyroid autoantibodies, and thyroid dysfunction in patients with psoriasis were analyzed. 

Results Available evidence indicates that patients with psoriasis have an increased risk of autoimmune thyroid diseases. In the meta-analysis by Zhang et al., including 253,313 psoriasis patients and 1,376,533 controls, psoriasis was associated with a significantly increased risk of AITD (OR = 1.76; 95% CI: 1.35–2.28), particularly Hashimoto’s thyroiditis (OR = 1.88; 95% CI: 1.50–2.35). Observational studies also demonstrated higher levels of anti-TPO and anti-TG antibodies, more frequent thyroid dysfunction, and ultrasonographic changes suggestive of thyroid autoimmunity among psoriasis patients.

Conclusions Psoriasis is associated with an increased prevalence of autoimmune thyroid diseases, especially Hashimoto’s thyroiditis. The observed relationship may result from shared immunological and genetic mechanisms. Further prospective and causal studies are required to better understand the nature of this association.