Oral Manifestations of Psoriasis: A Systematic Review ^†

1. Introduction

Psoriasis is a systemic, immune-mediated, inflammatory skin disease of unknown aetiology [1]. It affects 2–4% of the population in western countries and it is characterized by circumscribed, circular, red papules or plaques with a grey or silvery-white, dry scale.

Although many studies reported possible association between psoriasis and several oral conditions [2], some questions still remain unsolved.

The aim of this review was to analyze all the existing literature on oral manifestations in psoriatic patients and to determine their prevalence compared with healthy subjects.

2. Methods

PubMed, Scopus, and Web of Science were used as search engines. Only observational, full-length, English language studies were investigated. PRISMA checklist was used as guideline for this review. PROSPERO registration code is CRD42019127178.

3. Results

Among 3580 records screened, only 40 were included in this review. Meta-analysis was performed on the included case-control studies and mean prevalence and pooled odds ratio were calculated.

Among the included studies, the mean prevalence of geographic tongue was 11.80% in case group vs. 6.59% in control group (OR= 2.81, 95% CI 2.2–3.6); the mean prevalence of fissured tongue was 29.96% in case group vs. 13.90% in control group (OR = 2.93, 95% CI 2.5–3.5); the mean prevalence of periodontitis was 26.29% in case group vs. 11.48% in control group (OR = 3.5, 95% CI 2.49–4.23); the mean prevalence of candidiasis was 6.67% in case group vs 1.04% in control group (OR = 3.17, 95% CI 1.8–5.7); the mean prevalence of Candida spp. was 45.81% in case group vs. 20.53% in control group (OR = 3.79, 95% CI 2.3–6.4); the mean prevalence of TMD was 40.67% in case group vs. 16.96% in control group (OR = 2.94, 95% CI 1.1–7.9).

Due to dis-homogeneity across studies no quantitative analysis was performed on salivary biochemical composition. Nevertheless, psoriatic patients presented a lower mean concentration of salivary IgA, lysozyme and cortisol than controls, whereas IL-1β was higher.

4. Discussion

This systematic review revealed that geographic tongue, fissured tongue, periodontitis, candidiasis and TMD are more frequent in psoriatic patients than general population. Moreover, psoriatic patients showed biochemical alterations in the saliva composition compared to healthy subjects. Future research should be conducted to rule out the mechanism underlying these associations and to investigate the behavior of oral manifestation in psoriatic patients in relation to their severity and treatment response.