Keloid disorder is an active biological process. Over time, keloid lesions grow and become larger, and often merge with nearby keloids. Dr. Tirgan has pioneered the research in documenting this aspect of keloid disorder. A retrospective analysis of two large clinical datasets
was conducted. The first dataset comprised 1088 consecutive patients seen by Dr. Tirgan in his keloid specialty practice. The second dataset was obtained from an ongoing online keloid survey that Dr. Tirgan launched in November 2011. A total of 1,709 participants were asked to provide answers to numerous questions about their keloids, including an assessment of their keloids’ growth rates over time. Results of his research was published in a 2021 under the title of Cartesian Model of Keloid Growth.

The growth of keloid lesions over time can result in the merger of adjacent keloids. The blue arrow above points to the area where two adjacent keloids have now merged.