Distinguishing Mild, Moderate, and Severe Hidradenitis Suppurativa

Automated classification of hidradenitis suppurativa disease severity by convolutional neural network analyses using calibrated clinical images

BACKGROUND

The assessment of hidradenitis suppurativa (HS) severity requires detailed, and error-prone lesion counts. This proof-of-concept study aimed to automatically classify HS disease severity using machine learning of clinical smartphone images.

METHODS

777 ambient-light and size-controlled images were used to build a class-balanced synthetic dataset (n = 7675). Convolutional neural networks (CNN) were used for automated severity classification (scale 0-3), and to assess disease-dynamics. International Hidradenitis Suppurativa Severity Score System (IHS4) served as reference. A U-NET algorithm was implemented for automated localization of diseased skin.

RESULTS

CNNs were able to distinguish no/mild from moderate/severe disease with an overall prediction accuracy of 78% [receiver operating curve (AUC) 0.85]. Correct IHS4 classification was achieved with an overall accuracy of 72% (AUC 0.84-0.89). In addition, disease dynamics using IHS4 numerical values aligned with CNN outputs (NRMSE 0.262). The UNET algorithm localized lesions with a pixel accuracy of 88.1% and test loss of 0.42.

LIMITATIONS

Limitations in assessing tattooed and hairy skin. Limited number of patients with dark skin colour and Hurley I.

CONCLUSION

CNNs were able to distinguish no/mild from moderate/severe disease, classify disease severity over time, and automatically identify diseased skin areas and the skin phototype. This study breaks new grounds for fast, reliable, reproducible and easy-to-use HS severity assessments using clinical images.

Overview and comparison of the clinical scores in hidradenitis suppurativa: A real-life clinical data

Introduction

Partly due to its clinical heterogeneity, hidradenitis suppurativa (HS) is difficult to score accurately; illustrated by the large number of disease scores. In 2016, a systematic review by Ingram et al. reported the use of about thirty scores, and since then, this number has increased further. Our aim is twofold: to provide a succinct but detailed narrative review of the scores used to date, and to compare these scores with each other for individual patients.

Materials and methods

The review of the literature was done among articles in English and French, on Google, Google scholar, Pubmed, ScienceDirect and Cochrane. To illustrate the differences between scores, data from some Belgian patients included in the European Registry for HS were selected. A first series of patients compares the severity of the following scores: Hurley, Hurley Staging refined, three versions of Sartorius score (2003, 2007, 2009), Hidradenitis Suppurativa Physician Global Assessment (HS-PGA), International Hidradenitis Suppurativa Severity Scoring System (IHS4), Severity Assessment of Hidradenitis Suppurativa (SAHS), Hidradenitis Suppurativa Severity Index (HSSI), Acne Inversa Severity Index (AISI), the Static Metascore, and one score that is not specific to HS: Dermatology Life Quality Index (DLQI). A second set of patients illustrates how some scores change over time and with treatment: Hurley, Hurley Staging refined, Sartorius 2003, Sartorius 2007, HS-PGA, IHS4, SAHS, AISI, Hidradenitis Suppurativa Clinical Response (HiSCR), the very new iHS4-55, the Dynamic Metascore, and DLQI.

Results

Nineteen scores are detailed in this overview. We illustrate that for some patients, the scores do not predictably and consistently correlate with each other, either in an evaluation of the severity at a time-point t, or in the evaluation of the response to a treatment. Some patients in this cohort may be considered responders according to some scores, but non-responders according to others. The clinical heterogeneity of the disease, represented by its many phenotypes, seems partly to explain this difference.

Conclusion

These examples illustrate how the choice of a score can lead to different interpretations of the response to a treatment, or even potentially change the results of a randomized clinical trial.

Current Medical and Surgical Treatment of Hidradenitis Suppurativa-A Comprehensive Review

Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease presenting with recurrent inflammatory lesions in intertriginous body regions. HS has a pronounced impact on patients' quality of life and is associated with a variety of comorbidities. Treatment of HS is often complex, requiring an individual approach with medical and surgical treatments available. However, especially in moderate-to-severe HS, there is an urgent need for new treatment approaches. In recent years, increased research has led to the identification of new potential therapeutic targets. This review aims to give a comprehensive and practical overview of current treatment options for HS. Furthermore, the clinically most advanced novel treatment approaches will be discussed.

Hidradenitis suppurativa

Hidradenitis suppurativa (HS; also designated as acne inversa) is a chronic inflammatory disorder, which affects the intertriginous skin and is associated with numerous systemic comorbidities. The estimated prevalence of HS is ~1% in most studied countries. Typically starting in early adulthood, cutaneous inflamed nodules, abscesses and pus-discharging tunnels develop in axillary, inguinal, gluteal and perianal body sites. The comorbidities of HS include metabolic and cardiovascular disorders, which contribute to reduced life expectancy. A genetic predisposition, smoking, obesity and hormonal factors are established aetiological factors for HS. Cutaneous changes seem to start around hair follicles and involve activation of cells of the innate and adaptive immune systems, with pivotal roles for pro-inflammatory cytokines such as tumour necrosis factor, IL-1β and IL-17. The unrestricted and chronic immune response eventually leads to severe pain, pus discharge, irreversible tissue destruction and scar development. HS has profound negative effects on patients' quality of life, which often culminate in social withdrawal, unemployment, depression and suicidal thoughts. The therapeutic options for HS comprise antibiotic treatment, neutralization of tumour necrosis factor and surgical intervention together with lifestyle modification. Nevertheless, there is an enormous need for awareness of HS, understanding of its pathogenesis and novel treatments.