A Comprehensive Review of Non-Energy-Based Treatments for Atrophic Acne Scarring

Figures & data

Table 1 Atrophic Acne Scar Subtypes

Scar Type	Morphology
Ice Pick	Diameter: <2 mm Depth: Lower dermis/subcutis Visual: V-shaped, pitted appearance
Boxcar	Diameter: 1–4 mm Depth: Upper dermis (shallow) or lower dermis (deep) Visual: Round or geometric appearance with vertical walls and flat base
Rolling	Diameter: ≥4 mm Depth: Upper dermis Visual: Slopy, undulating appearance caused by fibrotic tether of dermis to subcutaneous layer

Notes: Adapted from J Am Acad Dermatol, 45(1), Jacob CI, Dover JS, Kaminer MS. Acne scarring: A classification system and review of treatment options. 109–117, copyright 2001, with permission from Elsevier.⁴

Figure 1 Visual representation of atrophic acne scar subtypes.

Notes: (A) Ice pick scars are narrow atrophic scars that can extend into the reticular dermis and, in some cases, down to the hypodermis. (B) Boxcar scars are oval- or rectangular-shaped depressions with vertical walls and a flat base. Shallow boxcar scars can extend into the papillary dermis but more severe boxcar scars can penetrate through the reticular dermis. (C) Rolling scars are the widest but shallowest scar type, rarely reaching down to the reticular dermis. They have a wavy or slope-like appearance on the skin. Created with Biorender.com.

Table 2 Categorical Overview of Chemical Peels

Type	Depth of Penetration	Common Examples
Superficial	Stratum corneum to stratum basale/upper papillary dermis	Glycolic acid, salicylic acid, lactic acid, retinoic acid, mandelic acid, pyruvic acid, Jessner’s peel, <35% TCA
Medium	Papillary dermis/upper reticular dermis	35–50% TCA, Glycolic acid + 35% TCA Jessner’s peel + 35% TCA
Deep	Upper reticular dermis/mid-reticular dermis	>50% TCA, 50–88% phenol, phenol-croton oil peels

Notes: Adapted from O’Connor AA, Lowe PM, Shumack S, Lim AC. Chemical peels: A review of current practice. Australas J Dermatol. 2018;59(3):171–181, © 2017 The Australasian College of Dermatologists.⁷

Table 3 Categorical Overview of Dermal Fillers

Type	Estimated Longevity	Common Examples
Short-Lasting (Temporary)	6–18 months	Hyaluronic acid (HA) Bovine/Porcine-sourced collagen
Semipermanent	20–24 months	Poly-L-lactic acid (PLLA) Calcium hydroxylapatite (CaHA)
Long-Lasting (Permanent)	>5 years	Polymethylmethacrylate (PMMA)

Notes: Adapted with permission from Dove Medical Press. Wollina U, Goldman A. Fillers for the improvement in acne scars. Clinical, Cosmetic and Investigational Dermatology. 2015;8:493–499.¹²²

Table 4 Clinical Efficacy of Acne Scar Treatments per Atrophic Scar Subtype

Scar Type	C/P	DA	MDA	SUB	MN	P/E	Filler	TL
Ice Pick	+++	+	+	+	+	+	+	*
Deep Boxcar	++	+	+	++	+	+++	++	*
Shallow Boxcar	++	++	++	++	++	-	++	*
Rolling	++	+	+	+++	++	-	+++	*

Notes: +++, Good; ++, Moderate; +, Poor; -, Not recommended; *, Lack of evidence.

Abbreviations: C/P, chemical peel; DA, dermabrasion; MDA, microdermabrasion; SUB, subcision; MN, microneedling; P/E, punch excision; TL, thread lifting.

Jacob CI, Dover JS, Kaminer MS. Acne scarring: a classification system and review of treatment options. J Am Acad Dermatol. 2001;45(1):109–117. doi:10.1067/mjd.2001.113451

 PubMed Web of Science ®Google Scholar

O’Connor AA, Lowe PM, Shumack S, Lim AC. Chemical peels: a review of current practice. Australas J Dermatol. 2018;59(3):171–181. doi:10.1111/ajd.12715

 PubMed Web of Science ®Google Scholar

Wollina U, Goldman A. Fillers for the improvement in acne scars. Clin Cosmet Investig Dermatol. 2015;8:493–499. doi:10.2147/CCID.S86478

 PubMed Web of Science ®Google Scholar