TY - CHAP M1 - Book, Section TI - Shape, Configuration, and Grouping of Lesions A1 - Burgin, Susan PY - 2021 T2 - Guidebook to Dermatologic Diagnosis AB - As we have seen in previous chapters, eruptions may manifest lesions with characteristic individual shapes, or characteristic configuration or arrangement of multiple lesions. These attributes of lesions and eruptions can be harnessed as diagnostic tools. As has been previously mentioned, shape is an inherent property of one individual lesion whereas configuration refers to the scheme or arrangement formed by confluent grouped lesions. Sometimes it is difficult to discern whether any given shape is made up of more than one lesion, and so, for convenience, the differential diagnoses of both shape and configuration are discussed in this chapter. For example, papules may be grouped together to form an annular configuration, as is seen in granuloma annulare. Or, a plaque of lichen planus may assume an annular shape if it is depressed in the center and raised at the periphery. Similarly, a line can be made up of a confluence of lesions (configuration), such as the confluent vesicles seen in poison ivy dermatitis, or of one lesion (a shape), such as in dermographism. SN - PB - McGraw-Hill Education CY - New York, NY Y2 - 2024/03/28 UR - accessmedicine.mhmedical.com/content.aspx?aid=1175058726 ER -