Pityriasis Rosea: A Comprehensive Classification

Abstract

Pityriasis rosea (PR) is an acute, self-limiting exanthematous disease associated with the endogenous systemic reactivation of human herpesvirus (HHV)-6 and/or HHV-7. The disease typically begins with a single, erythematous plaque followed by a secondary eruption with lesions on the cleavage lines of the trunk (configuration of a ‘Christmas tree'). The duration may vary from 2 weeks to a few months. Besides the typical presentation of PR, atypical forms have been described. The previous classifications of PR are mainly based on its atypical morphological features rather than on the pathogenetic mechanisms that underlie the different presentations of the disease. Notably, most of the morphologically atypical forms follow a course amenable to the classic form. The classification that we propose, taking into account the pathogenesis, clinical features, and course of the disease, is easy and intuitive and may be helpful in identifying the atypical forms of PR in order to avoid misdiagnosis and establish the best treatment options. Finally, this classification provides indications for managing potentially harmful forms of PR (such as PR in pregnancy) and PR-like eruptions.

Pityriasis Rosea during Pregnancy: Major and Minor Alarming Signs

“…The current findings are consistent with our previous studies, but seem more significant, because the number of patients is higher and further statistical processing of data, such as the logistic regression, has been added [1,5].…”

“…Pityriasis rosea (PR) is a self-limiting exanthematous disease associated with human herpesvirus (HHV)-6 and/or HHV-7 reactivation [1][2][3] which is more frequent in pregnant women than in the general population [4]. The exanthem typically begins with a single, round or oval erythematous scaly plaque (herald patch) usually situated on the trunk, the thigh, the upper arm, or the neck.…”

“…Several patterns of enanthems may be present and usually follow the course of the skin eruption, disappearing with it or a few days later. They are frequently associated with forms of PR different from the classic one [1][2][3][4].…”

Concurrent pityriasis rosea and Bell's palsy

“…This is demonstrated by high-avidity IgG antibody titres and HHV 6–7 plasma viraemia during PR presentation. Nonetheless, the difference in presentation and duration of HHV 6–7 viraemia may indicate differences in pathogenesis pathways between the child and adult 17 18. Our patient's clinical picture is actually more fitting with the classic type, with a longer time lapse between herald patch and widespread exanthema (14 days), longer duration of exanthema (8 weeks) and lack of mucosal involvement.…”

“…A new classification scheme has recently been devised that delineates the differences between classic, relapsing, persistent, paediatric, pregnancy and PR-like eruptions, with a focus on the pathogenesis, distribution, frequency of herald patch, mucosal involvement, systemic symptoms, histopathology, mean duration and therapeutic options. Paediatric PR is notable for a shorter time lapse between herald patch and generalised eruption (4 days vs 2 weeks), shorter exanthema duration (16 vs 45 days), increased mucosal involvement and higher viral plasma HHV 6–7 levels, but a similar per cent of patients presenting with systemic symptoms 3 17 18. In children as well as adults, viral reactivation, rather than primary infection, is thought to be the likely aetiology.…”