From the Research
Pityriasis rosea is likely caused by human herpesvirus 6 (HHV-6) and possibly human herpesvirus 7 (HHV-7), though the exact relationship remains under investigation. The most recent and highest quality study, published in 2021 1, suggests that HHV-6 and HHV-7 have been implicated as the causative agents in some patients with pityriasis rosea. This connection explains why pityriasis rosea often presents with prodromal symptoms similar to viral infections, such as fatigue, headache, and mild fever before the appearance of the herald patch and subsequent smaller lesions.
Key Findings
- Pityriasis rosea is a common acute, self-limited papulosquamous dermatosis that primarily affects children and young adults 1
- HHV-6 and HHV-7 DNA have been found in the skin lesions and blood of patients with pityriasis rosea, suggesting these viruses may reactivate from latency to trigger the characteristic rash 1
- The condition typically resolves spontaneously within 6-8 weeks without specific antiviral treatment 1
- While antivirals like acyclovir have been tried in some cases with mixed results, treatment generally focuses on symptom management with topical corticosteroids, antihistamines for itching, and phototherapy in persistent cases 2
Clinical Implications
- The viral etiology of pityriasis rosea explains why it rarely recurs, as patients likely develop immunity after the initial infection, similar to other viral exanthems 1
- A mild prodrome consisting of headaches, fever, malaise, fatigue, anorexia, sore throat, enlarged lymph nodes, and arthralgia is present in about 5% of patients 1
- The most common presenting sign, found in approximately 80% of patients, is a "herald" or "mother" patch which is larger and more noticeable than the lesions of the later eruption 1