Validation of the Spanish Acne Severity Scale (Escala de Gravedad del Acné Española--EGAE)

Several acne grading systems have been described, but consensus is lacking on which shows superiority. A standardized system would facilitate therapeutic decisions and the analysis of clinical trial data.

To assess the feasibility, reliability, validity and sensitivity to change of the Spanish Acne Severity Scale (EGAE).

A Spanish, multicentre, prospective, observational study was performed in patients with facial, back or chest acne assessed using EGAE, Leeds Revised Acne Grading system (LRAG) and lesion count. Clinicians answered 4 questions regarding EGAE use and time employed. Patients were evaluated at baseline and after 5±1 weeks. Four additional blinded observers, all dermatologists, evaluated patients' pictures using EGAE and LRAG.

In total, 349 acne locations were assessed in 328 patients. Of the dermatologists, 95.6% (CI: 92.9-97.5%) reported that EGAE was easy to use, and 75% used it in <3 minutes. Interobserver reliability of the EGAE scale was shown by a Kendall's W of 0.773 (p<0.001). EGAE and LRAG scales showed a high correlation (Spearman's correlation>0.85; p<0.001). EGAE mean score in treatment-compliant patients was significantly lower at follow-up than at baseline (2.14 vs. 1.57, p<0.001, Cohen's d=0.35).The pre-post-treatment difference in EGAE mean score in non-compliant patients was not significant (1.44 vs. 1.32, p<0.102) and Cohen's d was lower (0.19) than in compliant patients.

The use of EGAE to evaluate acne grade in daily clinical dermatological practice in Spanish centres has shown feasibility, high interobserver reliability, concurrent validity and sensitivity to detect treatment effects.