<prompt> Annular herald mother patch is seen inP. albaP. roseaPsoriasisNocardiasis  <response>: Pityriasis Rosea PR Etiology:- A virus HHV-7 more frequently, HHV-6 less frequently has often been incriminated. Morphology:- Herald patch Is the first lesion of PR and is seen in about 80 of patients. Oval lesions with wrinkled, salmon pink centre and collarette of scales at the periphery. Scales are attached just within leading edge and free towards the center. Secondary lesions:- Begin as scaly papules, which enlarge to form oval annular plaques similar to herald patch Are smaller, less scaly and less erythematous than herald patch. Are arranged characteristically: the long axis of patches runs downwards and outwards from the spine, along the lines of the ribs fir tree or Christmas tree appearance, Sites of predilection:- Trunk, along lines of cleavage. Sometimes in 20 of patients lesions occur predominantly on extremities and neck inverse pattern. Points for diagnosis:- PR is characterized by: Presence of herald patch in 80 of patients. Eruption consisting of erythematous, oval annular plaques with a peripheral collarette of scales. Typical distribution on the trunk fir tree appearance. Ref:-NEENA KHANNA; pg num:-53,54,55 