The diagnosis of nevus anemicus is not always easy.

Abstract

Nevus anemicus has a variable incidence according to different Authors and this variability probably depends on its poor visibility in normal conditions. The importance of nevus anemicus is mainly due to its greater frequency in subjects with neurofibromatosis 1 (NF1), so that even for its precocity it is often referred to as a minor diagnostic criterion of NF1 (1, 2) in the first years of life when most of the other criteria are missing.

The diagnosis of nevus anemicus can already be suspected with the history when the mother reports that she sees white spots in case of vasodilatation of the skin due to crying, sweating, fever. On physical examination, nevus anemicus presents with multiple whitish, roundish and grouped  lesions mainly in the upper thoracic region. The disappearance under finger pressure and the much greater evidence with rubbing are the most important physical signs.