• Autoimmune Diseases
• Infections
• Inflammation

To the Editor:

Ter Haar et al 1 report a new tool, Autoinflammatory Disease Damage Index (ADDI), to measure damage caused by autoinflammatory diseases. Although this preliminary instrument was for patients with familial Mediterranean fever, cryopyrin associated periodic syndrome, tumour necrosis factor receptor-associated periodic fever syndrome and mevalonate kinase deficiency, we found a great utility also in another auto inflammatory disease (AD), namely hidradenitis suppurativa (HS). HS is a chronic–relapsing, debilitating autoinflammatory disease affecting apocrine gland-bearing skin which is estimated to affect 1% of the population.2 It is occasionally inscribed into more complex autoinflammatory syndromes, such as PASH (pyoderma gangrenosum, acne and HS), or concurrent with other dysimmune conditions such as Crohn's disease.3 HS severity is variously assessed by static scores, such as Hurley's or Canoui-Poitrine, or dynamic ones, such as modified Sartorius' score.4 However, no scores are still present to quantify the persisting systemic damage caused by chronic inflammation in HS, thus we preliminarily adopted ADDI for our cohort of 47 cases of severe Hurley III HS. Interestingly, our patients manifested characteristically high scores for musculoskeletal (97.87%), reproductive (46.8%), developmental (38.3%), ocular (23.4%), renal/amyloidosis (25.53%), neurological (17.15%), serosal (6.38%) and ears (2.13%) items (table 1). Cognitive impairment was calculated as positive if IQ<80 as defined by neuropsychological assessment, namely Wechsler Intelligence Scale for Adults IV, or if Mini-Mental State Examination resulted in a score of <23. Despite the limited number of patients assessed, ADDI may be a promising tool to evaluate the long-term systemic outcome in HS also. Prospective validation in longitudinal studies is needed to validate ADDI also for HS in daily practice.