Types of Scars
The formation of acne stimulates inflammation, rupture of follicles, and other events that activates the body’s natural wound healing process. However, during this process, the restoration of the extracellular matrix (ECM) causes an imbalance between the enzymes activated to degrade the old/damaged ECM and the inhibitors of these enzymes. This results in the formation of either atrophic or hypertrophic scars (13). Atrophic scars,are the most common form of acne scarring and are identified by three main types:
Pox & Vaccination Scars
Vaccination scars are typically found as hypertrophic or keloid scars, but can appear atrophic in certain vaccines. Although not all result in scarring, vaccine scars were used as the markers of a successful vaccination (17-18).
Chicken pox scars take the form of atrophic scars, similar to acne scars, and are formed when the blisters from chicken pox become infected from over scratching. As a result, scar tissue is developed when healing the broken skin.
Vaccinia Virus (VACV) Vaccine
Though vaccination against smallpox ended in the 1970’s, those who received the vaccine were left with a rather small atrophic, yet noticeable scar. The vaccine was administered via a bifurcated needle multiple times in the same location, creating a lesion. The lesion eventually healed and became a scab before falling off and becoming a long lasting scar (19).
Myocobacterium bovis (BCG)
Unlike the vaccination against smallpox, tuberculosis vaccination commonly leaves a hypertrophic, raised, scar. The vaccine is administered via a needle that may produce a sore, appearing a few days later. As the sore heals, a scar is left in its place.
What causes a scar?
The way a wound heals depends on many internal and external factors. And while the mechanism by which scars form is not completely understood, it is thought to occur due to an imbalance in the remodeling process. Because tissue remodeling requires a fine balance between fibroblasts, myofibroblasts, immune cells, and growth factors in order to properly develop “new” tissues, the act of producing large amounts of “new tissue” (such as during large wound repair) can lead to an imbalance in this process and thereby scar tissue formation (12). Microneedling and other fractional treatments (fractional laser) attempt to bypass this by creating “islands” of micro-injuries that allow the body to react in a balanced manner, thereby creating tissues that mimic normal, healthy skin.
Wound healing may be influenced by diverse factors such as (12):
- Wound size
- Infection of the wound
- Location on the body
- How the wound was created
- Surgical technique
- Genetic predisposition
- Diet of individual
- Immune system
- Circulation surrounding the tissue
- Diseases or medications that may affect wound healing (e.g., diabetes mellitus)
As can be seen in the above list, the considerations that go into how an individual will scar are many and the process by which a scar forms and evolves can be somewhat complicated.
However, for many, a healthy lifestyle and proper care following an injury can lead to better aesthetics in the advent of any scar formation.
-  Fabbrocini G, Annunziata MC, D’Arco V, De Vita V, Lodi G, Mauriello MC, Pastore F, Monfrecola G. Acne scars: pathogenesis, classification and treatment. Dermatol Res Pract. 2010;2010:893080. doi: 10.1155/2010/893080. Epub 2010 Oct 14. PubMed [citation] PMID: 20981308, PMCID: PMC2958495
-  The Science of Acne. (n.d.). Retrieved August 12, 2015, from http://thescienceofacne.com/the-types-of-acne-scars/
-  Scars. (n.d.). Retrieved August 12, 2015, from http://www.hopkinsmedicine.org/healthlibrary/conditions/dermatology/scars_85,P00313/
-  Goel, A., & Shrivastava, P. (2010). Post-burn scars and scar contractures.Indian Journal of Plastic Surgery : Official Publication of the Association of Plastic Surgeons of India, 43(Suppl), S63–S71. doi:10.4103/0970-0358.70724
-  Jason, J., Archibald, L. K., Nwanyanwu, O. C., Kazembe, P. N., Chatt, J. A., Norton, E., … Jarvis, W. R. (2002). Clinical and Immune Impact ofMycobacterium bovis BCG Vaccination Scarring . Infection and Immunity,70(11), 6188–6195. doi:10.1128/IAI.70.11.6188-6195.2002
-  Tan, X., Chun, S., Pablo, J., Felgner, P., Liang, X., & Davies, D. H. (2012). Failure of the Smallpox Vaccine To Develop a Skin Lesion in Vaccinia Virus-Naïve Individuals Is Related to Differences in Antibody Profiles before Vaccination, Not After. Clinical and Vaccine Immunology : CVI, 19(3), 418–428. doi:10.1128/CVI.05521-11
-  Smallpox Vaccination Method. (n.d.). Retrieved August 13, 2015, from http://emergency.cdc.gov/agent/smallpox/vaccination/vaccination-method.asp