We did a study across many years where we looked at the colour of CMN overtime in the same people. We had a large number of people, took photographs, and recorded the colour of their CMN with a colour measurement machine. We looked at what happened to their CMN, in particular we looked at the CMN of people who had had it lasered or treated by another type of removal, like dermabrasion or curettage. These are techniques where the top of CMN is removed, scraped away and the bottom is still there. Laser does the same, it takes away the top and leaves the rest.
We were particularly interested in people who had been treated in part, part of their CMN had been treated and the other part had not. This happens, for example, when sensitive areas in the nappy area are not treated and the other parts are. However, the CMN is joined up, so in those cases we were able to show that laser therapy did not make any difference to the colour in the long run in the area that was lasered. There was a temporary lightening but then the colour of the CMN would come back, not always as dark as it had been at birth. When we looked at the parts that were not lasered, they had ended up exactly the same colour as the lasered area.
We realised the eventual colour of the CMN is actually dictated by your body’s own skin colour. If you are someone with a darker skin tone your CMN will be darker at birth and will probably stay dark. If, however you are somebody who is born with lighter skin then your CMN is often very dark at birth but will gradually lighten overtime. It looked like these treatments had made the CMN lighter, but this lightening would have happened anyway.
We don’t think any of these treatments work for colour, we don’t think they are good treatments for CMN.
We do not have data on whether these treatments can reduce lumps or bumps or prevent a CMN from developing complications or cancer.