Research has shown that individuals with darker Fitzpatrick skin types (III-VI) face a higher risk of developing post-inflammatory hyperpigmentation (PIH). According to studies, this increased susceptibility is due to larger melanosomes, increased melanin production, and a greater presence of eumelanin.
To better understand prevention strategies, a recent systematic review evaluated the effectiveness of various interventions in reducing PIH risk for individuals with skin of color. The findings revealed that consistent sunscreen use—especially when combined with anti-inflammatory ingredients—is the most effective method for preventing trauma-induced PIH.
Study Methodology
Researchers conducted a comprehensive literature search across multiple databases including MEDLINE, Embase, PubMed and Cochrane. Key terms employed included “post-inflammatory hyperpigmentation,” “hypermelanosis,” “hyperchromia,” and “dyschromia.”
Out of an initial pool of 3,205 articles, researchers ultimately included 14 studies representing 369 patients in the final analysis. The majority of included studies were randomized controlled trials (over 50%), with experimental studies (21%) and case reports (14%) comprising the remainder.
Patient Demographics
The study population consisted predominantly of women (72%), with a mean age of 38 years. A total of 42% of the participants had Fitzpatrick skin type III, 54% Fitzpatrick skin type IV, and 4% type V. Among the 369 patients included, 95% of the PIH cases resulted from laser therapy, primarily fractional carbon dioxide laser, while the remaining cases stemmed from ultraviolet-B (UVB) irradiation, and chemical peels.
Among the control group who received no intervention beyond their regular skincare routine, only 34% successfully prevented PIH, while 66% experienced failure in prevention.
Effective Interventions
Sunscreen emerged as the most common preventative measure studied showing remarkable results both alone and when combined with anti-inflammatory ingredients. When used by itself following laser treatments, sunscreen prevented PIH in 98% of cases over a two-month follow-up period. Similarly, when sunscreen was combined with anti-inflammatory ingredients like licochalcone A, L-carnitine, and avobenzone following laser procedures, it achieved a 100% success rate in preventing PIH over the same timeframe.
Less Effective Interventions
Epidermal growth factor (EGF) applications achieved only a 34% success rate despite being used by 13% of study participants. Though some improvement in PIH appearance was noted, the difference between treatment and control groups was insignificant, despite higher patient satisfaction in the treatment group.
Systemic tranexamic acid (TXA) generally failed to prevent PIH development across all studied cases. Oral TXA following QS Nd:YAG laser treatment showed no clinical difference between treatment and control groups at six weeks.
Topical antibiotics were generally unsuccessful in preventing PIH development. While fusidic acid cream applied twice daily for seven days after fractional CO2 laser treatment failed to prevent PIH completely, it did reduce severity with only a 2% increase in Hyperpigmentation Area and Severity Index Score after eight weeks.
Topical corticosteroids showed mixed results, preventing PIH in 58% of cases while failing in 42%. After fractional CO2 laser treatments, clobetasol application didn’t prevent PIH but significantly decreased its intensity and size. Clobetasol showed better results compared to hydrocortisone.
Perhaps most concerning were cooling air devices, which not only failed to prevent PIH in all cases but actually worsened outcomes. When applied to half the face during QS Nd:YAG laser treatment, cooling created a 2.6 times higher relative risk of developing PIH, with one patient developing persistent hyperpigmentation specifically on the cooled side of the face.
Study Limitations
Despite its findings, the study faces several limitations, including the lack of a standardized assessment scale for PIH and inconsistent photography methods. Furthermore, results didn’t include Fitzpatrick skin type VI or comparisons with non-skin of color individuals due to the exclusion criteria. Additionally, though the review focused on trauma-induced PIH, it’s important to note that PIH can result from both internal and external factors.
Conclusion
Researchers concluded by stating that, “While photoprotection is a promising preventative strategy, an educational gap exists wherein individuals with darker skin tones lack awareness regarding the significance of sunscreen usage. Many other interventions are far less effective and have only been studied on scarce sample sizes. In summary, there is substantial room for improvement in this area, and there is considerable optimism for enhancing preventative strategies in the future.”
Source:
- Prevention of Post-Inflammatory Hyperpigmentation in Skin of Colour: A Systematic Review. (n.d.). Australasian Journal of Dermatology. https://onlinelibrary.wiley.com/doi/full/10.1111/ajd.14432
