Acne scar can be a very important and serious issue in the treatment plan of patients with acne. Traditionally, people in Taiwan usually called the red or dark discoloration as “acne scar”, which is actually only post-inflammatory erythema (PIE) or post-inflammatory hyper-pigmentation (PIH) in the dermatological condition. That is why these discolorations are sometimes called “pseudo- acne scar” by dermatologists here in Taiwan.
The actual acne scar is the depression or protrusion of the skin caused by previous inflammatory papules, pustules, nodules or cysts. The true acne scar can be divided into depressed or hypertrophic ones. The former usually is further divided into 3 types: icepick, boxcar, or rolling type. Therefore, the communication between medical professionals and general population should be very careful and physicians should discuss with the patients what they really mean by “acne scar”.
Each of these different subtypes, including pseudo- or true acne scar, can be treated with various approaches from topical medicaments, glycolic acid peels, vitamin C sonophoresis, intralesional steroids or botulinum toxin injection, fillers injection, liquid nitrogen, or surgical technique to various type of energy based therapy like lasers, intense pulsed light (IPL), pulsed dye laser, plasma, or even radiofrequency.
The Post-inflammatory Erythema and Hyperpigmentation
The post-inflammatory hyper-pigmentation or erythema usually does not need any treatment. They always fade away gradually after months. The reason for hyper-pigmentation is the inflammation induced pigment incontinence in the dermis. The melanin deposits can be cleaned later by the macrophage in the dermis. The use of sunscreen, glycolic acid peel, vitamin C sonophoresis, topical medicaments like azelaic acid or retinoic acid, and even soft peel laser can help reducing the hyper-pigmentation faster.
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Glycolic acid peel used to be very popular in the past decades. Although subtle and slow, more than 50% to 70% of the patients had good improvement after 4 sessions of 35% or 50% glycolic acid (NeoStrata) peels 3 weeks apart, according to the report by Dr Chun-Min Wang et al. Nowadays, it is mostly replaced by mandelic acid peel because of its low irritancy.
As for the erythema, it is usually caused by severe inflammation induced vessel dilatation or proliferation. Therefore, IPL or long-pulsed dye laser is very helpful in this condition. The mostly used dye laser is a 595nm based purpura-free light device with dynamic cooling (Candela VBeam II). It is commonly called “Sakura laser” (櫻花雷射), probably due to its effectiveness on reducing red skin lesions. Other than destroying the dilated vessels, this laser also inhibits Propionebacterium acnes, suppresses sebaceous gland activity, stimulates transforming growth factor β (TGF-β) to produce collagen and inhibit melanogenesis.
-To be continued
