Persistent Hyperpigmentation Reported After Coretox Injections
Key Takeaways
- A 3-patient case series described persistent facial hyperpigmentation developing 2 to 3 weeks after Coretox botulinum toxin type A injections.
- All 3 events occurred with the same Coretox batch, and pigmentation persisted for more than 1 year despite several attempted treatments.
- The author hypothesized that polysorbate 20 could be a trigger, but the case series does not establish causality.
Persistent hyperpigmentation may represent a rare adverse event following Coretox botulinum toxin type A injections, according to a 3-patient case series published August 6 in Plastic and Reconstructive Surgery – Global Open.
The investigator reported 3 female patients who developed localized hyperpigmented macules after Coretox injections performed in 2024. Patients received subdermal injections in the forehead and periorbital regions and intramuscular injections in the glabellar region using standard aesthetic techniques.
Pigmentation Persisted Beyond 1 Year
Hyperpigmentation appeared at injection sites approximately 2 to 3 weeks after treatment. Serial QuantifiCare LifeViz imaging, including cross-polarized, ultraviolet-filtered, and hemoglobin-filtered imaging, showed increased melanin and hemoglobin signal intensity in affected areas. The patients reported no recent photosensitizer use, active dermatitis, or excessive ultraviolet exposure. Although pigmentation showed slight improvement over 2 to 3 months, discoloration persisted for more than 1 year in all 3 patients as of October 2025. Exosome-based treatment, Rejuran injections, and laser therapies were attempted without significant improvement.
The author reported using approximately 1,400 Coretox vials since 2019, with all 3 hyperpigmentation events associated with batch E622080A, dated June 28, 2024.
The mechanism remains uncertain. Kim proposed that polysorbate 20, a stabilizer used in Coretox in place of human serum albumin, could potentially trigger pigmentary changes in susceptible patients. The small case series and concentration of events within a single batch preclude conclusions regarding causality or incidence.
“Although the pathogenesis remains unclear, polysorbate 20 may act as a trigger in susceptible individuals,” the author concluded. “Early recognition, patient counseling, and photoprotection are recommended. Further investigation into excipient-induced pigmentary changes is warranted.”
Source
Kim, JS. Plastic and Reconstructive Surgery - Global Open. 2026;14(8):e7990. https://doi.org/10.1097/GOX.0000000000007990