Background: Severe nodular acne is characterized by inflammatory nodules and scarring. Their natural evolution and duration are insufficiently investigated.
Aim: To investigate the evolution and duration of untreated acne nodules.
Methodology: Four-week, single-centre, non-interventional, prospective study in subjects with severe nodular acne on the back. Nodule evolution and duration was assessed using standardized photographs taken twice weekly.
Results: Data from 23 subjects were evaluable. Mean age was 25.1 ± 4.9 years, 87% were males, and mean acne duration was 9.7 ± 6.7 years. At baseline, the overall total nodule count was 132 (mean number: 5.7 ± 3.0 nodules/subject). Among others, the following two main pathways were observed: nodules evolving directly into atrophic scars (31.8%) and nodules evolving towards papules into atrophic scars (37.9%). After 4 weeks, 77.3% of baseline nodules had evolved into atrophic scars. After baseline visit, a total of 247 new nodules (3.1 ± 2.2 nodules/week/subject) with a mean duration of 4.9 ± 2.6 days were observed. The mean duration of new nodules was significantly longer in subjects (n = 16) with ≥6 new nodules compared to subjects (n = 7) with <6 new nodules (5.2 ± 1.4 vs. 3.6 ± 0.8 days; P = 0.008)). There was no correlation between the number of new nodules and acne duration or with the number of baseline nodules.
Conclusion: This study documents the natural nodule evolution and duration over 4 weeks and showed in 23 patients the scarring potential of untreated severe nodular acne of the back.
© 2019 European Academy of Dermatology and Venereology.