Damage in hidradenitis suppurativa: receiving the deserved attention.

Hidradenitis suppurativa (HS) is a chronic disorder located mainly in the intertriginous body areas. HS is best known for its painful inflammatory skin lesions, such as inflammatory nodules, abscesses, and pus‐discharging tunnels. However, in this issue of the BJD, Fritsche et al. direct us to an overlooked aspect of HS, namely the postinflammatory damage.

Damage is a highly prevalent and burdensome aspect of HS, which is often neglected in clinical studies and clinical care. Such damage involves a broad range of scars (i.e. rope‐like, hypertrophic, bridged, plaque form), fibrotic bands (pseudo)comedones and dyspigmentation, which negatively impacts the quality of life of patients and can do so even after remission of disease activity. , To understand the relationship between the activity of HS, the progression of damage and the impact on patients, it is important to be able to measure the damage separately from disease activity.

The measurement of damage has been accepted in other inflammatory diseases, such as cutaneous lupus, dermatomyositis, pemphigus vulgaris, bullous pemphigoid, localized scleroderma, inflammatory bowel disease and rheumatoid arthritis. It is surprising that the assessment of damage in HS is only now following suit, despite the fact that HS is a highly damage‐inflicting disease. For example, the Crohn disease digestive damage score had already been proposed in 2011.

In this issue of the BJD, Fritsche et al. review current HS severity instruments incorporating scarring, damage outcome measures from other cutaneous diseases, and frequently used surgical scar or burn scales for usefulness in assessing damage in HS. Of the HS severity instruments that were reviewed, the Acne Inversa Severity Index (AISI) seemed most promising as it incorporates comedonal lesions, keloids/fibrotic adherence, fibrosclerotic inflammatory plaques and patient‐reported measures; however, the AISI only measured damage in combination with disease activity and could not capture forms of damage, such as physical limitations, atrophic scars or dispigmentation. There is much to be learned by examining the psychometric properties of the damage outcome measures used in other cutaneous diseases, but the morphology and body sites involved are too different for these instruments to be useful in HS. The (modified) Patient and Observer Scar Assessment Scale, a surgical scar scale, comes close to including the features required to assess postoperative HS scars, but does not account for damage in multiple anatomical regions and does not include other scar morphologies found in HS.

This narrative review shows that the measurement of damage is more established in other inflammatory (skin) diseases. However, the features of these instruments are not suitable for assessing damage in HS, which highlights the need for a damage measurement instrument developed specifically for HS. To measure the impact of damage in HS accurately, the patient perspective is crucial. Therefore, we encourage cooperation with the HIdradenitis SuppuraTiva cORe outcomes set International Collaboration, working alongside patients with HS and HS experts for developing this new instrument for measuring damage in HS.