Untreated severe nodular acne on the back often evolves to atrophic acne scars, and the duration of new nodules is longer in individuals who experience ≥6 new nodules vs <6 new nodules, according to study results published in the Journal of the European Academy of Dermatology and Venereology.

Patients (age range, 16-35 years) with severe nodular acne on the back were enrolled in the 4-week study. Severe nodular acne was defined as the presence of ≥2 nodules measuring 5 mm. Photographs of the back were taken at baseline and twice weekly every 3±1 days to assess changes of lesions. Specifically, the researchers evaluated photographs to identify the evolution of lesions to a nodule, papule, postinflammatory hyperpigmentation or an atrophic scar, complete clearance, or an undetermined status. The researchers also collected safety outcomes during the study period.

A total of 23 patients included in the study (mean age, 25.1±4.9 years) had a mean acne duration of 9.7±6.7 years. The overall total nodule count at baseline was 132 (mean, 5.7±3 nodules/patient). The most frequent changes in nodules included nodules that evolved into atrophic scars (31.8%) and nodules that evolved toward papules and then into atrophic scars (37.9%). At 4-week follow-up, the majority of nodules at baseline had evolved into atrophic scars (77.3%).

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A total of 3.1±2.2 new nodules/wk/patient, with a mean duration of 4.9±2.6 days, was observed after baseline visit, represented by a total of 247 new nodules. Duration of new nodules was longer in 16 patients with ≥6 new nodules vs 7 patients with <6 new nodules (5.2±1.4 vs 3.6±0.8 days, respectively; P =.008). No association was observed between acne duration with the number of new nodules or with the number of baseline nodules.

Limitations of the study included the small patient cohort as well as the lack of data on family history of acne scarring.

“To date, no [clinical] data about the evolution and duration of acne nodules have been published,” the researchers concluded. “The present data allow for the first time [appreciation of] the occurrence, evolution, duration and outcome of nodules in untreated severe nodular acne on the back.”

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Reference

Khammari A, Blanchet-Réthoré S, Bourdès V, et al. Evolution and duration of nodules in severe nodular acne on the back: results from a four-week non-interventional, prospective study. J Eur Acad Dermatol Venereol. 2019;33(3):601-607.