Validation of a visual-aided questionnaire for the self-assessment of hidradenitits suppurativa

Background: Hidradenitis Suppurativa (HS) is a chronic, highly debilitating disease. Few questionnaires have been developed to identify potential HS cases based on simple questions. A visual representation may help in characterising these lesions. Objective: To develop and validate a visually assisted questionnaire for HS detection. Methods: This was an observational diagnostic study on a series of patients with a first diagnosis of HS and a corresponding series of age and gender-matched controls consecutively observed in two Italian centres. The questionnaire was developed based on a critical appraisal of the relevant literature and on expert consensus. Measures of accuracy and reproducibility were assessed. Results: 57 patients with HS and 57 controls were included in the study (mean age 32.9 ± 12.3 years). Based on at least one affirmative answer to the proposed questionnaire items, the accuracy was 95.6%, with a sensitivity of 98.2% and a specificity of 93.0%. Reproducibility was almost perfect on all the tested items (Cohen's kappa ≥ 0.85). Limitations: The questionnaire was tested only in experimental conditions. Conclusion: The questionnaire could be a useful tool for HS screening in the general population. Further studies are needed to confirm its performance in a real-world setting.