Patients with palmoplantar pustulosis (PPP) with co-occurring plaque psoriasis have a higher incidence of psoriatic arthritis, according to a study published in the British Journal of Dermatology.

In this large observational study, investigators estimated the prevalence of PPP and co-occurring psoriasis in 3 population-based cohorts in the United States, Denmark, and Germany to determine patient demographics and characteristics.

In the US cohort (n=1435), individuals with at least 1 diagnostic record of PPP between October 1, 2015, and September 30, 2016, were identified using PPP diagnostic ICD-10 code L40.3; co-occurring psoriasis was identified using ICD-10 code L40.0 or ICD-9 code 696.1. In the Danish cohort (n=751), data on morbidity were obtained from the Danish National Patient Register. Data from the German cohort (n=1832) were obtained through The Statutory Health Insurance (SHI) nationwide dataset.

Prevalence of PPP in the US, Danish, and German cohorts had an estimated 1-year prevalence of 0.009%, 0.005%, and 0.08%, respectively. Subgroup analyses showed that in patients with PPP, 61.3%, 14.2%, and 36.4% had co-occurring psoriasis, respectively. Psoriatic arthritis was observed more frequently in patients with both PPP and psoriasis (21.8%, 25.2%, and 20.4%, respectively).

Medication usage was more prevalent in patients with PPP with co-occurring psoriasis. Among the 3 cohorts, patients in the US, followed by patients in Denmark, tended to use more potent topical corticosteroids compared with patients in Germany. Topical calcipotriol was most commonly used in the German cohort (25.8%) compared with the Danish cohort (18.2%) and the US cohort (9.5%). Patients with PPP with co-occurring psoriasis had a higher prevalence of using systemic therapies.

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This study was limited by the lack of available data on participants regarding morphology, severity, family history, and ethnicity, as well as body mass index, smoking habits, and other lifestyle factors. Genetic and ethnic differences may partially influence the risk of some comorbidities. Diagnostic challenges may have caused some misclassification of diseases due to random errors in diagnostic coding.

This study provides novel and valuable information about patients with PPP, an understudied patient population, in terms of demographics, comorbidities, and pharmacotherapy use, and “adds to [the] understanding of the disease burden of PPP with or without co-occurring psoriasis.”

Disclosures: Several authors acknowledge conflicts of interest. Please see the original reference for a full list of authors’ disclosures.

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Reference

Andersen YMF, Augustin M, Petersen J, et al. Characteristics and prevalence of plaque psoriasis in patients with palmoplantar pustulosis [published online February 28, 2019]. Br J Dermatol. doi: 10.1111/bjd.17832