Introduction
The future of measuring hidradenitis suppurativa is here thanks to Legit.Health's revolutionary AIHS4 (Automatic, International Hidradenitis Suppurativa Severity Scoring System). The researchers have developed a tool that processes smartphone images and automatically analyses them using the same criteria as the IHS4.
Is widely known that objective, reliable, and precise outcome measures are key to the practice of evidence-based medicine. In the case of hidradenitis suppurativa, the IHS4 is the most modern and reliable measurement tool, widely recommended for its use in clinical trials and daily practice. That's why Legit.Health has chosen it as a basis for its new and revolutionary technology.
The AIHS4 has been echoed in recent scientific publications, such as the following article by the National Research Council of Italy, and the Universities of Palermo and Messina:
(...) to overcome the IHS4, which is time-consuming and subject to variability, the AIHS4 is introduced, using a DL model, Legit.Health-IHS4net, for lesion detection (...). This evidence highlights the utility of AI in evidence-based dermatology, offering a potential tool to empower dermatologists in daily practice and clinical trials.
(...) The Automatic International Hidradenitis Suppurativa Severity Score System (AIHS4), an automatic equivalent of IHS4 that deploys a deep learning model for lesion detection, is a proof of concept with promising results. The algorithm assesses inflammatory nodules, abscesses, and draining tunnels allowing for supervision by physicians.
The origins of IHS4
Before the development of the IHS4 in 2017, other systems such as the Hurley classification or the Modified Sartorius Score were widely used by physicians. Although these older systems lacked granularity and precision, the absence of an alternative method made them widespread in both clinical practice and trials.
However, it [Hurley's classification] is static and was not designed as a dynamic score for accurate assessment of the extent of inflammation within each stage.
The IHS4 was developed with those issues in mind, and the panel of experts that put it together focused on reaching a more objective, precise, and reliable way of measuring the severity of hidradenitis suppurativa.
The formula developed by the panel of experts added the three more common symptoms of Hidradenitis suppurativa and multiplied them by a factor relevant to how indicative they were to the severity of the disease. This way, the number of nodules is multiplied by 1, the number of abscesses by 2, and the number of draining tunnels (fistulae/sinuses) by 4.
All of this added, make the IHS4 score. Said score is then compared against a small reference table that assigns an interpretable meaning to each bracket of scores.
- Less than 3 points: Mild
- Between 3 and 10 points: Moderate
- More than 11 points: Severe
Adapted from "Development and validation of the International Hidradenitis Suppurativa Severity Score System (IHS4), a novel dynamic scoring system to assess HS severity". C.C. Zouboulis, T. Tzellos, A. Kyrgidis et all, on behalf of the European Hidradenitis Suppurativa Foundation Investigator Group.
Limitations of the pen-and-paper IHS4
A precise classification of disease severity is based on the subjective assessment of the clinical manifestation by a physician, so the doctor's experience plays a significant role.
Despite its contributions to solving the issues of its predecessors, the IHS4 presents the same issues as many other scoring systems: a high degree of subjectivity derived from the visual nature of the test and a process reported by many doctors as too time-consuming and tedious.
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Stepping over digital calculators
The case of the IHS4 is a very special one. Unlike most dermatological scoring systems for other diseases, such as PASI or SCORAD, the relatively new development of this method has allowed the medical community to skip one common yet outdated step in the advancement of the state of the art for this field.
This step, consisting of developing a computer calculator, tries to tackle one of the main issues with any scoring system: The time needed to apply it properly. They do it by turning the many calculations the doctors usually need to make into an automatic process.
This is yet to happen in the diagnosis of hidradenitis suppurativa, as the IHS4 is a relatively young scoring system and there has not been enough time for one of these calculators to emerge.
Instead of that, with AIHS4, we are jumping right into the future of dermatology by addressing both the issues of time and objectivity within the traditional method.