The skin is carefully and thoroughly examined under a reflected light microscope (dermatoscope). This facilitates a 10-fold magnification in which we can clearly recognise pigment marks and light damage as well as skin changes as signs of squamous cell carcinomas.
The so-called ABCDE rule is applied to the assessment of birthmarks:
A – Asymmetry
B – Boundary with weak, serrated edges
C – Colour/uneven pigmentation
D – Diamete r> 5 mm
E – Evolution/change of the pigmentation mark in the last three months
If one of these criteria applies to a pigment mark, we examine it more intensively.