A narrative review of the definition of ‘flare’ in hidradenitis suppurativa

Abstract

Summary Background Hidradenitis suppurativa (HS) is a chronic, inflammatory condition that can have periodic worsening or flares. Measurement of flare is important because it can inform treatment efficacy; however, it is unclear how HS flare should be defined. Objectives This study reviewed the literature for definitions of HS flare. Methods The PubMed MEDLINE online database was searched on 10 January 2018 and the search was repeated on 8 December 2018 for new publications. Titles and abstracts were screened for inclusion. Subsequently, full articles were screened for inclusion. Papers were included if the publication was a systematic review, clinical trial, cohort study, case report or series, or cross‐sectional study. Studies were excluded if they were journalistic reviews, did not discuss clinical findings of HS or did not use the words ‘flare’, ‘exacerbation’, ‘relapse’ or ‘recurrence’. Results Two hundred and seventy‐four papers were identified and 154 fulfilled the study criteria. Of these, 27 (17.5%) included the term ‘flare’ and 16 (10.4%) included the term ‘exacerbation’. Two of the 27 papers (7%) defined the term flare and both included patient report of changes in symptoms or signs. One of 16 papers (6%) defined exacerbation, which was taken as one new HS lesion. The terms ‘recurrence’ and ‘relapse’ were more apt to be defined: 13% (13 of 100) and 14% (six of 44), respectively. Conclusions The lack of a specific and measurable definition of HS flare is a barrier to assessment of this important outcome. Once a specific and measurable definition is established, validated and reliable measures of HS flare can be incorporated into future studies. What's already known about this topic? Hidradenitis suppurativa (HS) is a chronic, relapsing inflammatory skin condition. The ability to assess flares is important to people who have HS; however, it is unclear how this is defined. HS flare is one of the core outcomes in the core outcome set for HS clinical trials; however, it is unclear how this should be assessed. What does this study add? This literature review reveals the paucity of measurable definitions associated with the use of the term ‘flare’ in the HS literature. It also highlights the variation and lack of a validated and reliable measure of HS flare.

Periodic worsening, or flare, in hidradenitis suppurativa: the perspective of people with hidradenitis

“…4 Yet a recent literature review demonstrated that there are few precise definitions of HS flare. 5 Notably, it is the person with HS who experiences flare and there is little data pertaining to the lived experience of people with HS to inform flare definition. The aim of this study was to explore the patient perspective of HS flare.…”

“…These findings differ from existing definitions, which focus on changes in clinical exam. 5 Thus, there are differences in the lived experience of patients with HS and the definitions in prior studies. The findings of the study should be considered with its limitations.…”

Consensus definitions of disease activity in hidradenitis suppurativa: crossing the semantic gap

“…There have been several review articles on cutaneous mucinoses in the literature with suggested classifications. 1,2 Most commonly, cutaneous mucinoses have been classified into primary (metabolic) or secondary (catabolic) processes. 1 Although secondary mucinoses are usually incidental mucin deposits seen on histology only and can be seen in numerous dermatological conditions, 2 occasionally secondary mucin deposition can produce macroscopic deposits of mucin, leading to clinical lesions as has been reported in connective tissue disorders.…”

“…Kirby et al . 's narrative review in this issue of the BJD is a vital first step in the development of consensus definitions of disease flare, which in turn may lead us to more clinically relevant measures of disease activity. The counting of nodules is highly relevant for mild‐to‐moderate HS in the absence of scarring, tunnel formation and diffuse oedema/lymphoedema.…”

“…Kirby et al . 's work is a vital first step in establishing consensus definitions, but patient viewpoints are vital to ensuring that the existing semantic gap can be bridged. Only with the help of our patients can we strive to appropriately measure outcomes as well as measure the appropriate outcomes.…”