Annular herald (mother) patch is seen in

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