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This is a relatively common skin rash that first presents with a solitary scaly patch, usually on the upper trunk, known as the Herald Patch. After a few days, a papulo-squamous eruption occurs on the upper trunk and extremities, often taking the appearance of a christmas tree. Although the etiology is still unknown, a viral cause has long been suspected.


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SYNONYMS Pityriasis rosea of Gilbert

An epidemiological study of pityriasis rosea in Middle Road Hospital.

Cheong WK, Wong KS.

Singapore Med J 1989 Feb;30(1):60-2 Abstract quote

Pityriasis rosea is a common skin disorder seen in dermatological practices. A one year prospective study on pityriasis rosea was carried out in Middle Road Hospital, Singapore. A total of 214 patients were studied.

The incidence rates by age, sex and month were analysed. The peak incidence was in the 20-24 age group. There was a male predominance. More patients with pityriasis rosea were seen in the months of March, April and November. The clinical features in our patients concur with other studies. Blood for VDRL was done on 170 patients. Two had a biological false positive test. Total white counts were normal in 97.9% of specimens done.

The rash lasted from 1 to 8 weeks in 84.4% of the patients with most patients suffering from the rash for 5 weeks.


One-year review of pityriasis rosea at the National Skin Centre, Singapore.

Tay YK, Goh CL.

National Skin Centre, Singapore.

Ann Acad Med Singapore 1999 Nov;28(6):829-31 Abstract quote

Pityriasis rosea is a common, acute, self-limited papulosquamous eruption of possible viral aetiology.

The aim of this study was to describe the profile of pityriasis rosea seen at a referral skin centre in Singapore. A retrospective chart review was conducted of all the patients with a diagnosis of pityriasis rosea seen during 1996. There were 368 patients; their ages ranged from 9 months to 82 years with a peak in the 20 to 29 years age group. There were slightly more males (1.2:1). The clinic incidence was 6.5 per 1000 cases. No ethnic predilection was noted and cases were seen evenly throughout the year. About a quarter of the patients gave a history of a viral infection shortly before or during the occurrence of the rash. Most cases had a typical truncal distribution. The herald patch was observed in 63 patients (17%). Inverse distribution involving mainly the extremities were seen in 22 cases (6%) and eczematised lesions were noted in 20 cases (5.4%). The two main differential diagnoses considered were tinea infection and secondary syphilis. A fungal scrape and a rapid plasma reagin test were done in 58 and 59 patients, respectively, and the results were negative. Treatment was symptomatic and consisted of topical steroids and antihistamines. Thirty patients (8%) were given oral prednisolone for extensive eruptions.

The pattern of pityriasis rosea in Singapore is similar to that reported in other countries except for a male predominance and absence of monthly variation. A lower incidence and an older group of patients were also seen in our series as compared to African patients.


Epidemiological study of human herpesvirus-6 and human herpesvirus-7 in pityriasis rosea.

Kosuge H, Tanaka-Taya K, Miyoshi H, Amo K, Harada R, Ebihara T, Kawahara Y, Yamanishi K, Nishikawa T.

Department of Dermatology, Tokyo Electric Power Hospital, 9-2 Shinanomachi, Shinjuku-ku, Tokyo 160-0016, Japan.

Br J Dermatol 2000 Oct;143(4):795-8 Abstract quote

BACKGROUND: Pityriasis rosea (PR) is a common papulosquamous skin disorder that is suspected to have an infectious aetiology.

OBJECTIVES: We aimed to study the role of human herpesvirus (HHV)-7 and HHV-6 in the pathogenesis of PR.

METHODS: We performed seroepidemiological studies (indirect immunofluorescence test) and polymerase chain reaction (PCR) analysis for HHV-6 and HHV-7 in patients with PR. Seventy-two serum samples and 37 samples of peripheral blood mononuclear cells (PBMC) from 44 patients with PR were obtained. Twenty-five patients with other skin disorders such as drug eruption, urticaria or herpes zoster were studied as controls in the PCR analysis.

RESULTS: HHV-7 DNA was detected in 13 of 30 (43%) samples of PBMC of the patients with PR and 14 of 25 (56%) samples of PBMC of controls. HHV-6 DNA was detected in six of 29 (21%) patients with PR and nine of 23 (39%) controls. Thus there was no difference in the prevalence of HHV-6 or HHV-7 in PBMC between patients with PR and those with other skin disorders. In the seroepidemiological study, two cases of at least a fourfold rise in titre and five cases of a fourfold decrease in titre to HHV-7 antibody, and two cases of a fourfold rise in titre and two cases of a fourfold decrease in titre to HHV-6 antibody, were observed in 24 patients with PR. This seroepidemiological study revealed antibody responses consistent with active infection in several PR patients, but the greater proportion of the patients had no definite increase in the antibody titres.

CONCLUSIONS: We conclude that HHV-7 and HHV-6 may play a part in some patients with PR, but that other causative agents may exist. Further analyses are needed to determine the causative agents of PR.

Association of pityriasis rosea with human herpesvirus-6 and human herpesvirus-7 in Taipei.

Wong WR, Tsai CY, Shih SR, Chan HL.

Department of Dermatology, Chang Gung Memorial Hospital, 199 Tung Hwa North Road, Taipei, Taiwan.

J Formos Med Assoc 2001 Jul;100(7):478-83 Abstract quote

BACKGROUND AND PURPOSE: Pityriasis rosea (PR) is a common papulosquamous skin disease with unknown etiology. The possible relationship of PR with human herpesvirus infection (HHV) has been extensively studied. This study used the polymerase chain reaction (PCR) to investigate the presence of human herpesvirus 6 and 7 (HHV-6 and HHV-7) in 41 PR patients from two hospitals in Northern Taiwan. The epidemiologic features of PR in patients were also studied.

METHODS: A total of 41 PR patients (11 males, 30 females) were enrolled in this study from April 1999 to March 2000. PCR of skin biopsy specimens from 24 PR patients was used to identify the existence of HHV-6 and HHV-7. Viral culture from PR biopsy specimens was also performed. Blood from these patients was sampled for Venereal Disease Research Laboratory tests. Skin biopsies from 20 age- and sex-matched controls with other skin diseases were also subjected to PCR study.

RESULTS: The ages of the 41 PR patients ranged from 8 to 62 years. An increased incidence (17/41) of PR episodes was observed during the spring. Both HHV-6 and HHV-7 DNA was below the limit of detection in all biopsy specimens from patients and healthy controls. Viral culture for HHV was negative in all patients.

CONCLUSION: The epidemiologic features of PR in this series are comparable to other studies except for an exaggerated female predominance (male:female ratio 1:2.7). Our data indicate a lack of association between HHV-6 and HHV-7 infection and PR.

Human herpesvirus 6 and 7 DNA in peripheral blood leucocytes and plasma in patients with pityriasis rosea by polymerase chain reaction: a prospective case control study.

Chuh AA, Chiu SS, Peiris JS.

Department of Medicine, University of Hong Kong, China.

Acta Derm Venereol 2001 Aug-Sep;81(4):289-90 Abstract quote

An association between pityriasis rosea and human herpesvirus 7 (HHV-7) has been reported but remains controversial. The purpose of the present study was to investigate the association between HHV-6 and HHV-7 with pityriasis rosea. Fifteen patients aged 6-54 years with a diagnosis of pityriasis rosea and 15 age-matched controls were recruited.

None of the patients had HHV-6 or HHV-7 DNA detected by polymerase chain reaction in the acute or convalescent plasma specimen. In the acute peripheral blood leucocytes specimen, 3 patients and one control had RHV-6 DNA detected (p=0.299; NS), while 7 patients and 5 controls had HHV-7 DNA (p=0.355; NS). Antibody to HHV-6 was detected in the acute specimen of 13 patients and 13 controls, while antibody to HHV-7 was found in all 15 of patients and controls.

We thus found no evidence of recent HHV-6 or HHV-7 infection in patients with a diagnosis of pityriasis rosea.

Lack of evidence of active human herpesvirus 7 (HHV-7) infection in three cases of pityriasis rosea in children.

Chuh AA, Peiris JS.

Department of Medicine, University of Hong Kong, Hong Kong.

Pediatr Dermatol 2001 Sep-Oct;18(5):381-3 Abstract quote

Three cases of pityriasis rosea in Chinese children are presented. Using polymerase chain reaction for detection of human herpesvirus 7 (HHV-7) DNA in plasma and peripheral blood lymphocytes, we find no evidence of active HHV-7 infection.

Human herpes virus-like particles in pityriasis rosea lesions: an electron microscopy study.

Drago F, Malaguti F, Ranieri E, Losi E, Rebora A.

Section of Dermatology, Genoa, Italy Department of Health Sciences, DiSEM, University of Genoa, Italy Department of Pathology, Gaslini Institute, Genoa, Italy.

J Cutan Pathol 2002 Jul;29(6):359-61 Abstract quote

Background: In a previous study we detected virions with electron microscopy features of human herpes viruses in the supernatant of cocultured mononuclear cells from patients with acute pityriasis rosea. Because of their morphology and of polymerase chain reaction studies, we ascribed them to human herpes virus 7.

Objective: To find such virions in the lesional skin of pityriasis rosea patients.

Methods: Skin speciments from lesions of 21 patients with acute pityriasis rosea were examined by elecron microscopy.

Results: In 15 (71%) patients, human herpes virus particles in various stages of morphogenesis were detected. Mature enveloped virions appeared as typical human herpes virus virions, measuring about 160-200 nm in diameter and containing an electrodense cylindrical core, a capsid, an envelope with typical spikes and a very distinct tegument layer between the capsid and the envelope. They were very similar to those we reported in the supernatant of co-cultured circulating mononuclear cells from patients with pityriasis rosea.

Conclusion: Our results confirm our previous findings and provides further evidence of a viral etiology for pityriasis rosea.




The use of digital epiluminescence dermatoscopy to identify peripheral scaling in pityriasis rosea.

Chuh AA.

Department of Medicine, University of Hong Kong, Hong Kong, People's Republic of China.

Comput Med Imaging Graph 2002 Mar-Apr;26(2):129-34 Abstract quote

Non-digital epiluminescence dermatoscope (ED) is a skin surface microscope utilizing oil immersion. Digital ED achieves epiluminescence by cross-polarization, with real-time images shown on computer screen.Non-digital and digital ED can assist to identify peripheral scaling in pityriasis rosea (PR).

Additional advantages of digital ED include higher magnifications, a dry and convenient procedure, direct patient involvement, and easy appreciation of the relationship between microscopic changes and macroscopic clinical signs. PR is a particularly good teaching model as the histopathological changes almost exactly mirror changes seen under digital ED. Digital ED also allows easy image storage for record keeping, teaching and research.



Localized pityriasis rosea.

Ahmed I, Charles-Holmes R.

Department of Dermatology, Walsgrave Hospitals NHS Trust, Coventry, UK.

Clin Exp Dermatol 2000 Nov;25(8):624-6 Abstract quote

Pityriasis rosea is a relatively common skin disorder. In its typical form it is easily recognizable; however, atypical forms can pose diagnostic problems. We report a 44-year-old woman with an acute onset of a localized eruption on her left breast.

The morphology of the rash and the time course were typical of pityriasis rosea. Localized pityriasis rosea is an unusual variant, which has been described previously.


Oral lesions in pityriasis rosea.

Kay MH, Rapini RP, Fritz KA.

Arch Dermatol 1985 Nov;121(11):1449-51 Abstract quote

Oral lesions are not commonly reported with pityriasis rosea (PR).

We encountered a patient with clinical and histologic evidence of PR who developed aphthous ulcer-like oral lesions on the buccal mucosa, palate, and tongue. The oral lesions resolved concomitantly with the patient's skin lesions.

The previous literature reports a wide variety of oral lesions in association with PR, but few dermatologists, to our knowledge, are aware of such an occurrence.


Pityriasis rosea in children. A review.

Cavanaugh RM Jr.

Clin Pediatr (Phila) 1983 Mar;22(3):200-3 Abstract quote

Pityriasis rosea is a common disorder of unknown etiology that may simulate a number of other dermatologic entities. Secondary syphilis should always be ruled out, particularly in adolescents. Pruritus occurs more frequently than is generally appreciated. The herald patch may not always be present. Secondary lesions occasionally occur distal to the elbows and knees and on the face.

Over the more proximal parts of the body the secondary lesions will characteristically align themselves with the long axis following the skin lines of cleavage. The natural course is that of spontaneous resolution within 6 to 8 weeks. Sequelae are rare and usually medically insignificant.

Management with oral antipruritics and/or topical steroids may be necessary to relieve the itching.



Histopathology of pityriasis rosea Gibert. Qualitative and quantitative light-microscopic study of 62 biopsies of 40 patients.

Panizzon R, Bloch PH.

Dermatologica 1982;165(6):551-8 Abstract quote

62 biopsies of 40 patients with pityriasis rosea Gibert (PRG) were analyzed qualitatively and quantitatively.

The main histopathological feature is eczematoid. In addition, the following characteristics, especially in combination, are helpful for the differential diagnosis: absence or decrease of the granular cell layer, erythrocytes in the papillary dermis and partly in the epidermis, and homogenization of the collagen of the papillary dermis.

Recent and older lesions show little difference although the number of eosinophils in the inflammatory infiltrates has generally increased.

Dyskeratotic degeneration of epidermal cells in pityriasis rosea: light and electron microscopic studies.

Okamoto H, Imamura S, Aoshima T, Komura J, Ofuji S.

Br J Dermatol 1982 Aug;107(2):189-94 Abstract quote

We studied biopsies from twenty-nine patients with pityriasis rosea. All specimens showed features of subacute or chronic dermatitis as previously reported, but sixteen cases (55%) had dyskeratotic cells within the epidermis.

Ultrastructurally, these cells contained an aggregation of tonofilaments, many vacuoles and intracytoplasmic desmosomes. Previously, only non-specific histological changes had been described in pityriasis rosea, but the presence of dyskeratotic cells seems to be a significant feature.




Light and electron microscopic studies of pityriasis rosea.

el-Shiemy S, Nassar A, Mokhtar M, Mabrouk D.

Int J Dermatol 1987 May;26(4):237-9 Abstract quote

Light and electron microscopic studies of biopsy specimens taken from five patients with pityriasis rosea revealed the most conspicuous finding to be the presence of dyskeratotic cells within the epidermis.

Ultrastructurally, these cells contained an aggregation of tonofilaments, intracytoplasmic desmosomes, many vacuoles, and viral-like particles. It is assumed that pityriasis rosea is caused by a virus to which these changes are related.


Asymmetric periflexural exanthem of childhood  

Asymmetric periflexural exanthem of childhood: a clinical, pathologic, and epidemiologic prospective study.

Coustou D, Leaute-Labreze C, Bioulac-Sage P, Labbe L, Taieb A.

Unite de Dermatologie Pediatrique, Hopital Pellegrin-Enfants, Bordeaux, France

Arch Dermatol 1999 Jul;135(7):799-803 Abstract quote

OBJECTIVE: To assess the clinical, pathologic, and epidemiologic features of asymmetric periflexural exanthem of childhood (APEC), a clinically distinctive eruption, especially its link with pityriasis rosea and pattern of transmission.

DESIGN: A prospective case series, including an analysis of epidemiologic triggering factors and mode of transmission. Pathologic study, including immunohistochemistry of the inflammatory infiltrate.

SETTING: A mixed, community-based referral center.

PATIENTS: A total of 37 girls and 30 boys with typical APEC referred from April 1994 to December 1996 were included in the study; 82% came from the greater Bordeaux area in France.


MAIN OUTCOME MEASURE: Possible interhuman transmission of APEC.

REUSLTS: No triggering factor was identified; no interhuman transmission occurred; and no demonstrable link with pityriasis rosea was apparent. Several new clinical variants were recognized or confirmed (high fever, facial and peripheral involvement, prolonged course). Distinctive perisudoral interface CD8+ infiltrate was suggestive of diagnosis.

CONCLUSIONS: Interhuman transmission was doubtful, but inoculation disorder was still possible. Histopathologic findings seem more specific than previously thought.



Erythromycin in pityriasis rosea: A double-blind, placebo-controlled clinical trial.

Sharma PK, Yadav TP, Gautam RK, Taneja N, Satyanarayana L.

Department of Dermatology, Dr Ram Manohar Lohia Hospital, New Delhi, India.

J Am Acad Dermatol 2000 Feb;42(2 Pt 1):241-4 Abstract quote

BACKGROUND: The study stemmed from an incidental observation of improvement in 2 patients with pityriasis rosea while receiving erythromycin.

OBJECTIVE: The purpose of the study was to evaluate the efficacy of erythromycin in patients with pityriasis rosea.

METHODS: A double-blind, placebo-controlled clinical study was performed in an outpatient setting in a major hospital. Ninety patients over a period of 2 years were alternatively assigned to treatment group or placebo group. Patients in the treatment group received erythromycin in divided doses for 14 days. The response was categorized as complete response, partial response, or no response. All patients were followed up for 6 weeks.

RESULTS: Both groups were comparable with regard to age at presentation, sex, and average duration of disease at the time of reporting to the clinic. Upper respiratory tract infection before the appearance of skin lesions was reported in 68.8% of all patients. Complete response was observed in 33 patients (73.33%) in the treatment group and none in the placebo group (P <.0001).

CONCLUSION: Oral erythromycin was effective in treating patients with pityriasis rosea.

Prospective case-control study of chlamydia, legionella and mycoplasma infections in patients with pityriasis rosea.

Chuh AA, Chan HH.

The Bonham Surgery, Shop B5, Ning Yeung Terrace, 78 Bonham Road, Ground Floor, Hong Kong, China.

Eur J Dermatol 2002 Mar-Apr;12(2):170-3 Abstract quote

A double-blind placebo-controlled trial reported the benefit of erythromycin in treating pityriasis rosea (PR), a postulated mechanism being the eradication of bacteria susceptible to erythromycin.

The aim of this study was to investigate the association between PR and Chlamydia pneumoniae, C. trachomatis, Legionella longbeachae, L. micdadei, L. pneumophila, and Mycoplasma pneumoniae infections. We recruited 13 patients aged seven to 46 years (mean: 26.8 years) diagnosed to have PR in a primary care setting in 18 months. Lesional histopathology was arranged for atypical cases. Clotted blood was collected at initial presentation and four weeks later. Controls were 13 paired age-and-sex-matched patients requiring blood collection for non-dermatological diseases. Serology tests were performed in parallel but were read "blinded" on the acute and convalescent specimens of patients and the control subjects. The serology profiles were not diagnostic of active infection by any of the bacteria studied for all 13 patients. Two patients had four-fold increase in IgG titres against C. pneumoniae, with IgM being negative. Two patients had IgM detectable against L. pneumophila serotype 6 and M. pneumoniae respectively, with no significant rise of the specific IgG. These patients had no symptom or sign of chest infection. The seroprevalence and IgG titres of the study patients for the bacteria investigated were insignificantly different from those of control subjects.

We conclude that the bacteria investigated in this study do not play a significant role in the pathogenesis of PR. We believe that anti-inflammatory and immunomodulatary effects might contribute towards the action of erythromycin, if any, in PR.

Weedon D. Weedon's Skin Pathology. Churchill Livingstone. 1997.
Fitzpatrick's Dermatology in General Medicine. 5th Edition. McGraw-Hill. 1999.

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