L'ACCRESCIMENTO DEI FRATTALI NELLA GENESI DELLE DERMATOSI FIGURATE ANULARI ED ARCIFORMI

The concepts of fractal geometry have developed rapidly because the methods of this new mathematical branch have provided an explanation for various problems relating to apparently irregular natural forms: for instance, the shape of a coastline recognizes fractal forms as the basis of its morphology. Thus it has been natural to apply fractal models to the genesis of dermatological lesions: this has been done by a German group. Anyway, a fractal is not a static entity. Fractals can grow, and the new concept of fractal growth, pointed out by mathematical and physical research, is credited by us with great importance for the explanation of figurate lesion development in dermatology. Annular and arciform lesion growth is traditionally ascribed to the centrifugal diffusion of pathogens (either molecular or biotic), but such a concept cannot explain by itself the astonishing levels of complexity reached by clinical dermatological lesions: radial diffusion of molecules in 'in vitro' systems produces only dull-round-shaped haloes. In fact we believe that the new concept of fractal diffusion-limited growth, which is strictly related with the new concept of 'chaotic natural processes', could be a strong research tool in explaining why some typical dermatologic clinical lesions should retain their characteristic figurate shapes throughout their course and simultaneously present an extraordinary variety of growth patterns. Such ideas could prove useful in teaching activities, too.