Pityriasis @entity21361 (PRP) is an idiopathic @entity203 which can be difficult to distinguish from @entity1569 . We explored the clinical features, including background medical illnesses and potential triggers in @entity1 with PRP, and also its histomorphologic spectrum. @entity1 with PRP were selected by natural language search of dermatopathology databases containing 250,000 cases accessioned over a 3-year period. A detailed medical history was obtained on each @entity1 via office chart review and @entity1 interviews. We compared the histologic findings in skin biopsies from @entity1 with PRP to those of biopsies matched for site and age from control @entity1 with @entity1569 . Certain aspects of the clinical presentations encountered in the study group @entity1 have not been previously emphasized, including eruptions compatible with a @entity74 in 4 @entity1 . Several @entity1 had evidence of underlying iatrogenic or systemic immune dysregulatory states and certain triggers could be isolated such as emotional stress and prior exposure to microbial pathogens. Histomorphologic features predictive of PRP included follicular plugging, an increased granular cell layer, and acantholysis. While seen in a minority of biopsies of PRP, morphologic discriminators supportive of a diagnosis of @entity1569 included neutrophils in the parakeratotic scale crust, and @entity1829 capillary @entity4122 with vessels lying in direct apposition to the epidermis. Other morphologic features were encountered in biopsies of PRP which have received little emphasis in the dermatopathology literature, including @entity194 , significant dermal @entity32 , the presence of eosinophils and plasma cells within the inflammatory infiltrates, an abnormal granular cell layer, and @entity5656 , albeit none were statistically signficant predictors of PRP over @entity1569 . Nevertheless, their identification emphasizes the varied histologic spectrum of PRP. The almost ubiquitous finding of acantholysis and the presence of an abnormal granular cell layer in many biopsies of PRP suggests that abnormal keratins or defects in the retinol signalling pathway may be of pathogenetic importance.

The clinical and histomorphological features of XXXX . A comparative analysis with @entity1569 .

@entity1 :: ('9606', 'Species') :: ['Patients', 'patients', 'patient'] @entity32 :: ('MESH:D007249', 'Disease') :: ['inflammation'] @entity21361 :: ('MESH:D010916', 'Disease') :: ['rubra pilaris'] @entity4122 :: ('MESH:D004108', 'Disease') :: ['ectasia'] @entity1569 :: ('MESH:D011565', 'Disease') :: ['psoriasis'] @entity5656 :: ('MESH:D017488', 'Disease') :: ['epidermolytic hyperkeratosis'] @entity203 :: ('MESH:D003875', 'Disease') :: ['erythematous scaling eruption'] @entity1829 :: ('MESH:D010211', 'Disease') :: ['dermal papillae'] @entity194 :: ('MESH:D001284', 'Disease') :: ['epithelial atrophy'] @entity74 :: ('MESH:D030342', 'Disease') :: ['vesiculobullous disorder']
@entity21361 :: (MESH:D010916,Disease) :: ['pityriasis rubra pilaris']
