In view of an updated classification of mastocytosis (Table 1),1 it seems appropriate to present a historical note on the Darier sign. Urticaria pigmentosa (UP) is the most common manifestation of cutaneous mastocytosis. Comparable skin findings in systemic mastocytosis are called UP-like or UP-type. The typical lesions appear as reddish to deep-brown macules or papules scattered over the body. Darier sign refers to the urtication and erythematous halo that are produced in response to the rubbing or scratching of these lesions. Long before Darier's description of the phenomenon, many dermatologists, as well as numerous mothers, knew how easily the macules transformed when they were irritated. Basic articles on the subject were written by Nettleship,2 who, in 1869, described a chronic urticaria that left brown stains, and by Sangster,3 who coined the term urticaria pigmentosa in 1878.
Skrabs CC. Darier Sign: A Historical Note. Arch Dermatol. 2002;138(9):1253-1254. doi:10.1001/archderm.138.9.1251