A Novel Patient-Centered Severity Measure for Pilonidal Disease: A Retrospective Cohort Study

Pilonidal disease is common in adolescents and young adults and can impair daily functioning during an important developmental phase. This study aimed to develop and validate a pilonidal disease severity score based on patient-reported symptom burden and social quality of life, and compare it with the International Pilonidal Society classification, an anatomy-based system categorizing pilonidal disease by location and distribution.

Retrospective review of patients with pilonidal disease presenting to a Pilonidal Care Clinic (January 2023-August 2025). Of 620 new patients, 447 met inclusion criteria and were analyzed, with 299 in the derivation cohort and 148 in the validation cohort. Symptom burden score (0-18) was calculated. Quality of life was measured across six domains (each 0-10) and reduced to a three-domain score (0-30). Multivariable linear regressions adjusted for age and gender were used.

Nidus and rash were associated with 2.57 and 2.45-point increases, respectively, in the 18-point symptom burden score (P < 0.001, 95% confidence interval: 1.53-3.60; P < 0.001, 95% confidence interval: 1.10-3.80). One point was assigned for three or more pits, 0 for wound, and 10 each for nidus and rash, yielding mild (0-1), moderate (10-11), and severe (20-21) categories. Symptom burden increased across categories in both cohorts (P < 0.001). Severity category was also associated with worse social quality of life (P < 0.001, P = 0.006); International Pilonidal Society classification was not correlated with either.

A patient-centered pilonidal disease severity score may improve severity classification and comparability of outcomes across studies.