SEARCH RESULTS FOR: Pityriasis-Rosea

Pityriasis Rosea

Pityriasis Rosea: Pathogenesis and clinical findings Authors: Leah Johnston Reviewers: Lauren Lee Stephen Williams Ben Campbell Laurie Parsons* * MD at time of publication Pityriasis Rosea Epidermal layer Dermal-Epidermal Junction Dermal layer Psoriasiform hyperplasia, parakeratosis, spongiosis and Preceding viral infection, reactivation of latent Human Herpesvirus (HHV-6 or HHV-7) Female sex (2:1 female to male ratio) Risk factors Recent vaccinations: Bacillus Calmette-Guerin (BCG), influenza, H1N1, diphtheria, smallpox, hepatitis B, and Pneumococcus Red blood cell lymphocytes extravasation Perivascular dermal infiltrates: lymphocytes, monocytes, and eosinophils Spongiosis (intercellular fluid accumulation in epidermis) Erythematous, pink-salmon or brown coloured lesions Altered production of melanin by epidermal melanocytes Post-inflammatory hyperpigmentation or hypopigmentation Prodromal symptoms: fatigue, nausea, headaches, joint pain, enlarged lymph nodes, fever, and/or sore throat Age 10 to 35 Exact mechanism unknown Activation of T-cell mediated host immune response ↑ Signal proteins in serum including interleukin 17 (IL-17), interferon gamma (IFN-γ), vascular endothelial growth factor (VEGF), and induced protein 10 (IP-10), leading to increased capillary permeability Spring and fall seasons Fluid extravasation from blood vessels Red blood cell extravasation Often asymptomatic, can be pruritic Cell infiltration isn’t as intense or doesn’t produce as dramatic an inflammatory response as other skin conditions ↑ CD4 lymphocytes, monocytes, eosinophils and Langerhans cell infiltration into the dermis and epidermis Pityriasis Rosea Activation of B cells and production of anti- keratinocyte IgM antibodies Parakeratosis (incomplete keratinocyte maturation) and proliferation of epidermal cells (known as psoriasiform hyperplasia) Thickened epidermal layer Scale A self-limited, papulosquamous eruption that is characterized by round or oval-shaped, erythematous to brown patches or plaques with scaling borders that typically occur on the trunk and proximal extremities and tend to follow Langer’s lines. Often initially presents with a larger herald patch as the first sign. Legend: Pathophysiology Mechanism Sign/Symptom/Lab Finding Complications Published January 30, 2023 on www.thecalgaryguide.com