Psoriasis is a dermatological disease that manifests itself in the appearance of spots covered with silvery-white scales on the skin. Elbows, knees, scalp and the area near the sacrum are the most commonly affected regions. When the spots appear in traumatized areas, Koebner is mentioned as a phenomenon, which affects about 25% of psoriatic patients.

This phenomenon may be triggered by several factors. If you have psoriasis, a tattoo could trigger Koebner’s phenomenon and make the patches appear just near the tattoo.


The Koebner phenomenon

As Professor Antonio Costanzo, Head of Dermatology at Humanitas and lecturer at Humanitas University explains: “Koebner’s phenomenon is unpredictable. Today we know that the mechanism at the base of the phenomenon is the release of small proteins (antimicrobial peptides) by damaged skin cells and methylated DNA that together act as “triggers” for the activation of cells of the innate immune system, thus triggering the inflammatory reaction that manifests in the formation of psoriatic plaque. The extent of the release of these factors is not predictable and therefore we cannot know whether a trauma will trigger psoriasis.

The size of the tattoo is not proportional to the risk of developing a psoriatic blotch. We also have to consider the fact that some pigments (yellow and red) can induce greater activation of the immune system because they are irritant or immunogenic.


Psoriasis may become symptomatic after tattooing

The tattoo could also trigger the manifestation of the disease, which until then may have been in remission. This happens “with any physical or psychological trauma affecting a person genetically predisposed to develop the disease,” explains Professor Costanzo.

Injection of pigments into the skin interferes with the skin’s balance and may induce an even more serious inflammatory reaction, which may lead to the appearance of psoriatic spots in subjects who have remained asymptomatic.