<prompt> A 5 yr old male child has multiple hyperpigmented macules over the trunk. On rubbing the lesion with the rounded end of a pen, he developed uicarial wheal confined to the border of the lesion. Most likely diagnosis:FDELPUicaria pigmentosaUicarial vsaculitis  <response>: Gentle rubbing of a lesion causes local itching, erythema, and wheal formation after 2-5 minutes which may be present for 30 min or few hrs. This is the Dariers sign and is seen in uicaria pigmentosa. 