Abstract:White dermographism constitutes an abnormal vascular reaction characteristically demonstrable in atopic dermatitis; however, there is no information about it in the infantile phase of atopic dermatitis. Therefore we examined 73 infants younger than 3 years of age with eczematous dermatitis for the demonstrablity of white dermographiam after mechanical strocking of the lesional skin. None of the 40 healthy control infants showed white dermographism on their normal skin. In contrast, an age‐dependent increase was demonstrated in patients with infantile eczema, from 11% in those 1 to 2 months of age to 85% in those older than 7 months. There was no correlation between the demonstrabllity of white dermographism in early infancy and the prognosls of infantile eczema. Based on our study of various types of dermatitis experimentally induced in adult volunteers, we think that, in addition to the immaturity of infantile skin, the presence of acute dermatitic changes may be related to Inabllity to demonstrate with dermographism in the early phase of infantile eczem