The challenge of palmoplantar pustulosis therapy: Are Interleukin-23 inhibitors an option?

Palmoplantar Pustulosis: A Systematic Review of Risk Factors and Therapies

Palmoplantar pustulosis (PPP) is a chronic, relapsing, inflammatory disease that can occur alone or in association with arthritis. There is still controversy about whether it should be separated from psoriasis or classified as pustular psoriasis. Furthermore, drug-induced paradoxical PPP is a special variant of PPP that differs from classic PPP in several ways. Treatment of PPP is still challenging, and there are a number of treatment-resistant cases. This review summarizes the risk factors for the development of PPP and the currently available treatment modalities. Female sex, smokers or ex-smokers, obesity, thyroid dysfunction, and treatment with a tumor necrosis factor (TNF)-α inhibitor have been identified as risk factors for the disease's development, severity, and course. Topical treatments and phototherapy are effective for some patients and are used as a first-line or adjuvant treatment modality. Conventional treatments including retinoids and fumaric acid show good effects and can increase the efficacy of treatment with psoralen + ultraviolet light therapy (PUVA). Ciclosporin is fast acting, but relapse mostly occurs immediately after cessation. TNF-α inhibitors are efficient, and an even better response can be achieved with IL-17 and IL-23 blockers as well as apremilast. The effect of Janus kinase inhibitors seems to be promising according to case reports, but further investigations with larger cohorts are needed.

Risks of Comorbidities in Patients With Palmoplantar Pustulosis vs Patients With Psoriasis Vulgaris or Pompholyx in Korea

Importance

Palmoplantar pustulosis (PPP) has been reported to be accompanied by systemic conditions. However, the risks of comorbidities in patients with PPP have rarely been evaluated.

Objective

To assess the risks of comorbidities in patients with PPP compared with patients with psoriasis vulgaris or pompholyx.

Design, Setting, and Participants

This nationwide population-based cross-sectional study used data from the Korean National Health Insurance database and the National Health Screening Program collected from January 1, 2010, to December 31, 2019. Data were analyzed from July 1, 2020, to October 31, 2021. Korean patients diagnosed with PPP, psoriasis vulgaris, or pompholyx who visited a dermatologist between January 1, 2010, and December 31, 2019, were enrolled.

Exposures

Presence of PPP.

Main Outcomes and Measures

The risks of comorbidities among patients with PPP vs patients with psoriasis vulgaris or pompholyx were evaluated using a multivariable logistic regression model.

Results

A total of 37 399 patients with PPP (mean [SD] age, 48.98 [17.20] years; 51.7% female), 332 279 patients with psoriasis vulgaris (mean [SD] age, 47.29 [18.34] years; 58.7% male), and 365 415 patients with pompholyx (mean [SD] age, 40.92 [17.63] years; 57.4% female) were included in the analyses. Compared with patients with pompholyx, those with PPP had significantly higher risks of developing psoriasis vulgaris (adjusted odds ratio [aOR], 72.96; 95% CI, 68.19-78.05; P < .001), psoriatic arthritis (aOR, 8.06; 95% CI, 6.55-9.92; P < .001), ankylosing spondylitis (aOR, 1.91; 95% CI, 1.61-2.27; P < .001), type 1 diabetes (aOR, 1.33; 95% CI, 1.16-1.52; P < .001), type 2 diabetes (aOR, 1.33; 95% CI, 1.29-1.38; P < .001), Graves disease (aOR, 1.25; 95% CI, 1.11-1.42; P < .001), Crohn disease (aOR, 1.63; 95% CI, 1.11-2.40; P = .01), and vitiligo (aOR, 1.87; 95% CI, 1.65-2.12; P < .001) after adjusting for demographic covariates. The risks of ankylosing spondylitis (aOR, 1.37; 95% CI, 1.16-1.62; P < .001) and Graves disease (aOR, 1.40; 95% CI, 1.23-1.58; P < .001) were significantly higher among patients with PPP vs psoriasis vulgaris. However, the risks of psoriatic arthritis (aOR, 0.54; 95% CI, 0.47-0.63; P < .001), systemic lupus erythematosus (aOR, 0.67; 95% CI, 0.46-0.97; P = .04), Sjögren syndrome (aOR, 0.70; 95% CI, 0.50-0.96; P = .03), systemic sclerosis (aOR, 0.29; 95% CI, 0.11-0.77; P = .01), vitiligo (aOR, 0.53; 95% CI, 0.47-0.60; P < .001), and alopecia areata (aOR, 0.88; 95% CI, 0.81-0.95; P = .001) were significantly lower among those with PPP vs psoriasis vulgaris.

Conclusions and Relevance

The results of this cross-sectional study suggest that patients with PPP have an overlapping comorbidity profile with patients with psoriasis vulgaris but not patients with pompholyx. However, the risks of comorbidities among patients with PPP may be substantially different from those among patients with psoriasis vulgaris.