TRASS Is Effective Grading Tool for Truncal Acne

acne at back of body
acne at back of body
Researchers sought to provide dermatologists with an easy-to-use tool to assess truncal acne.

The truncal acne severity scale (TRASS) is an effective tool to assess the severity of truncal acne, investigators reported in study data published in the Journal of the European Academy of Dermatology and Venereology.

The researchers sought to provide dermatologists with an easy-to-use tool to assess truncal acne with use of a global approach to patients’ disease and family history of acne, clinical examination, and perceived impact on their quality of life.

The methodology used to build and test TRASS was similar to that used for the Global Evaluation Acne, Echelle de Cotation des Lésions d’Acné, and Adult Female Acne Scoring Tool scales.

TRASS is based on 3 subscores. Subscore number 1 includes data considered as predictive markers of severity and disease history, including duration of acne, family history, and past isotretinoin treatments. Subscore number 2 identifies and rates the acne located on the trunk regarding the number of nodules, presence and types of scars, and presence of acne on the face. Subscore number 3 assesses the effect of truncal acne on the patient’s quality of life. The total truncal acne score ranges from 0 to 19.

The first regression optimized (ROP) model analysis used the median value as the discriminant value. The coefficients suggested that family history, facial acne, and quality of life were not required to discriminate patients with a median TRASS greater than 10 compared with the other items. The average error rate calculated on the evaluation samples was 6.6 ± 8.0%, with a range of 0% to 29.4%.

Patients with the most severe acne were identified with a linear score derived by adding the values for acne duration, systemic treatments, lesion area, number of nodules, and scars.

The ROP analysis used the 75th percentile as the discriminant value, and only the coefficient of facial acne was equal to zero. Internal testing without this item demonstrated an average error rate equal to 10.4 ± 9.5%, with a range of 0% to 41.2%.

Previous systemic treatments were significantly correlated with the number of nodules (0.338, P =.01988) and scars (0.430, P =.0025). A statistically significant correlation was found between areas on the trunk and effect on quality of life (0.374, P =.0095).

A sensitivity analysis showed that the absence of variables not selected by the ROP model did not lead to any change in the final model. In addition, the absence of the variables that were initially retained resulted in significant modifications in the final model.

“TRASS is the first global and patient-centered approach to evaluate truncal acne,” stated the researchers. “It scores the importance of each factor that plays a role in the management of the condition, independently from its clinical severity. Based on this approach, TRASS may allow practitioners to choose and validate the most suitable therapy together with the patient in order to treat his or her truncal acne successfully and to limit treatment failure.”

Disclosure: This work has been funded by Galderma International, France, and the authors received honoraria from Galderma International, France, for participating in the expert group. Please see the original reference for a full list of disclosures.


Auffret N, Nguyen JM, Leccia M-T, Claudel JP, Dréno B. TRASS: a global approach to assess the severity of truncal acne. J Eur Acad Dermatol Venereol. 2022;36(6):897-904. doi: 10.1111/jdv.18009