DermNetPityriasis Rosea

Pityriasis rosea presents as a self-limiting rash characterized by a herald patch followed by smaller scaly oval patches. This comprehensive review details its clinical presentation, demographics, potential causes, and treatment approaches, providing physicians with essential guidance for diagnosis and management.

Key Points:

• The condition primarily affects teenagers and young adults (10-35 years), with a slightly higher prevalence in women and an incidence rate of 0.5% to 2%, predominantly occurring in winter months
• Viral infections (particularly HHV-6/7), drug reactions (including ACE inhibitors, NSAIDs, and various other medications), and vaccines (BCG, H1N1, COVID-19, among others) have been identified as potential triggers
• Up to 69% of patients experience prodromal flu-like symptoms before rash development, while 25% report mild to severe itching during the active phase
• The diagnostic hallmark involves a 2-5 cm herald patch followed by smaller secondary lesions appearing within weeks, typically distributed in a “Christmas tree” pattern along relaxed skin tension lines
• Treatment focuses on symptom management through moisturizers, topical steroids, and antihistamines, with evidence suggesting potential benefit from short-course aciclovir in severe cases

HCN Medical Memo
Although pityriasis rosea remains a self-limiting condition, early recognition of atypical presentations and awareness of potential complications, particularly in pregnant patients within the first 15 weeks of gestation, should guide clinical decision-making and patient counseling.

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