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A multi-centre, cross-sectional study of the clinical and demographic factors that influence the severity of palmoplantar pustulosis: Findings from the APRICOT, PLUM and ERASPEN consortia

Research output: Contribution to journalArticle

The APRICOT and PLUM study team, The ERASPEN consortium

Original languageEnglish
JournalJAMA dermatology
Publication statusAccepted/In press - 23 Jun 2020

King's Authors


Importance: While palmoplantar pustulosis (PPP) can have a profound impact on quality of life, the factors underlying disease severity have not been studied.

Objective: To define the factors associated with PPP severity.

Design: We undertook an observational, cross-sectional study of two cohorts. A UK dataset was recruited through the APRICOT clinical trial (2016-2019) and its sister research study PLUM (2016-2020). A Northern European cohort was independently ascertained by the European Rare And Severe Psoriasis Expert Network (2013-2017).

Settings: Patients were recruited in secondary or tertiary dermatology referral centres.

Participants: The UK and Northern European cohort included 203 and 193 cases, respectively. All were or European descent. PPP was diagnosed by dermatologists, based on clinical examination and/or published consensus criteria.

Main outcomes and measures: Demographics, comorbidities, smoking status, Palmoplantar Pustulosis Area Severity Index (PPPASI) or Physician Global Assessment (PGA).

Results: Among the 203 UK patients (43 males, 160 females; median age of onset [IQR] 48 [38-59] years), the PPPASI was inversely correlated with age of onset (r=-0.18, P=0.014). Similarly, in the 159 Northern European cases that were eligible for inclusion in this analysis (25 males, 134 females ; median age of onset [IQR] 45 [34-53.3] years), the median [IQR] age of onset was lower in individuals with moderate-to-severe PGA compared to those with mild-to-clear PGA 41 [30.5-52] vs 46.5 [35-55], P=0.043).
In the UK sample, the median [IQR] PPPASI was higher in females than males (9.6 [3.0-16.2] vs 4.0 [1.0-11.7], P=0.0096). Likewise, moderate-to-severe PPP was more prevalent among Northern European females compared to males 57 of 134 [43%] vs 5 of 25 [20%], P=0.026).
In the UK cohort, the median PPPASI [IQR] was elevated in current smokers compared to ex- and non-smokers (10.7 [4.2-17.5] vs 7 [2.0-14.4] vs 2.2 [1-6], P=0.003). Comparable differences were observed in the Northern European dataset, as the prevalence of moderate-to-severe PPP was higher in former/current smokers compared to non-smokers (51 of 130 [39%] vs 6 of 24 [25%], P=0.14).

Conclusions and relevance: PPP severity is associated with early-onset disease, female sex and smoking status. Thus, smoking cessation intervention might be beneficial.

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