Reactivation of human herpesvirus 6 in pityriasis rosea

Update on human herpesvirus 7 pathogenesis and clinical aspects as a roadmap for future research

Human herpesvirus 7 (HHV-7) is a common virus that is associated with various human diseases including febrile syndromes, dermatological lesions, neurological defects, and transplant complications. Still, HHV-7 remains one of the least studied members of all human betaherpesviruses. In addition, HHV-7-related research is mostly confined to case reports, while in vitro or in vivo studies unraveling basic virology, transmission mechanisms, and viral pathogenesis are sparse. Here, we discuss HHV-7-related literature linking clinical syndromes to the viral life cycle, epidemiology, and viral immunopathogenesis. Based on our review, we propose a hypothetical model of HHV-7 pathogenesis inside its host. Furthermore, we identify important knowledge gaps and recommendations for future research to better understand HHV-7 diseases and improve therapeutic interventions.

Association between Pityriasis Rosea (PR) and HHV-6/HHV-7 Infection: Importance of Sample Selection and Diagnostic Techniques

Recent studies have focused on the role of human herpesvirus 6 (HHV-6) and human herpesvirus 7 (HHV-7) in PR etiology with varying results. In our study, with the approach that the discrepancy between the results may be related to the different samples and techniques used, we aimed to clarify the etiology by examining tissue and plasma samples using molecular methods and evaluating the results together with serological parameters. Skin biopsies and plasma samples of twenty-five PR patients were tested to detect HHV-6 and HHV-7 DNA using calibrated quantitative real-time polymerase chain reaction (CQ RT-PCR). IgG and IgM antibodies against HHV-6 and HHV-7 were tested by enzyme-linked immunosorbent assay and indirect immunofluorescence. Of the patient group, 64% were positive for HHV-6 IgG without IgM positivity. HHV-6 DNA was present in seven tissue and ten plasma samples. HHV-7 positivity was 100% and 12% for IgG and IgM antibodies, respectively. HHV-7 DNA was detected in four tissue samples and one plasma sample. Patients with HHV-7 DNA-positive plasma and tissue samples had also HHV-7 IgM antibodies. In conclusion, our results seem to support the role of HHV-6/HHV-7 in the etiology of PR. To clarify the etiology of PR and avoid confusion, the collection of different biological materials simultaneously and the usage of CQ RT-PCR as a diagnostic technique are recommended.

Interventions for pityriasis rosea

BACKGROUND

Pityriasis rosea is a scaly, itchy rash that mainly affects young adults and lasts for 2 to 12 weeks. The effects of many available treatments are uncertain. This is an update of a Cochrane Review first published in 2007.

OBJECTIVES

To assess the effects of interventions for the management of pityriasis rosea in any individual diagnosed by a medical practitioner.

SEARCH METHODS

We updated our searches of the following databases to October 2018: the Cochrane Skin Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We searched five trials registers. We also checked the reference lists of included and excluded studies, contacted trial authors, scanned the abstracts from major dermatology conference proceedings, and searched the CAB Abstracts database. We searched PubMed for adverse effects to November 2018.

SELECTION CRITERIA

Randomised controlled trials of interventions in pityriasis rosea. Treatment could be given in a single therapy or in combination. Eligible comparators were no treatment, placebo, vehicle only, another active compound, or placebo radiation treatment.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by the Cochrane. Our key outcomes were good or excellent rash improvement within two weeks, rated separately by the participant and medical practitioner; serious adverse events; resolution of itch within two weeks (participant-rated); reduction in itch score within two weeks (participant-rated); and minor participant-reported adverse events not requiring withdrawal of the treatment.

MAIN RESULTS

We included 14 trials (761 participants). In general, risk of selection bias was unclear or low, but risk of performance bias and reporting bias was high for 21% of the studies. Participant age ranged from 2 to 60 years, and sex ratio was similar. Disease severity was measured by various severity indices, which the included studies did not categorise. Six studies were conducted in India, three in Iran, two in the Philippines, and one each in Pakistan, the USA, and China. The included studies were conducted in dermatology departments and a paediatric clinic. Study duration ranged from 5 to 26 months. Three studies were funded by drug manufacturers; most studies did not report their funding source. The included studies assessed macrolide antibiotics, an antiviral agent, phototherapy, steroids and antihistamine, and Chinese medicine. None of the studies measured participant-rated good or excellent rash improvement. All reported outcomes were assessed within two weeks of treatment, except for adverse effects, which were measured throughout treatment. There is probably no difference between oral clarithromycin and placebo in itch resolution (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.47 to 1.52; 1 study, 28 participants) or rash improvement (medical practitioner-rated) (RR 1.13, 95% CI 0.89 to 1.44; 1 study, 60 participants). For this comparison, there were no serious adverse events (1 study, 60 participants); minor adverse events and reduction in itch score were not measured; and all evidence was of moderate quality. When compared with placebo, erythromycin may lead to increased rash improvement (medical practitioner-rated) (RR 4.02, 95% CI 0.28 to 56.61; 2 studies, 86 participants, low-quality evidence); however, the 95% CI indicates that the result may also be compatible with a benefit of placebo, and there may be little or no difference between treatments. Itch resolution was not measured, but one study measured reduction in itch score, which is probably larger with erythromycin (MD 3.95, 95% CI 3.37 to 4.53; 34 participants, moderate-quality evidence). In the same single, small trial, none of the participants had a serious adverse event, and there was no clear difference between groups in minor adverse events, which included gastrointestinal upset (RR 2.00, CI 0.20 to 20.04; moderate-quality evidence). Two trials compared oral azithromycin to placebo or vitamins. There is probably no difference between groups in itch resolution (RR 0.83, 95% CI 0.28 to 2.48) or reduction in itch score (MD 0.04, 95% CI -0.35 to 0.43) (both outcomes based on one study; 70 participants, moderate-quality evidence). Low-quality evidence from two studies indicates there may be no difference between groups in rash improvement (medical practitioner-rated) (RR 1.02, 95% CI 0.52 to 2.00; 119 participants). In these same two studies, no serious adverse events were reported, and there was no clear difference between groups in minor adverse events, specifically mild abdominal pain (RR 5.82, 95% CI 0.72 to 47.10; moderate-quality evidence). Acyclovir was compared to placebo, vitamins, or no treatment in three trials (all moderate-quality evidence). Based on one trial (21 participants), itch resolution is probably higher with placebo than with acyclovir (RR 0.34, 95% CI 0.12 to 0.94); reduction in itch score was not measured. However, there is probably a significant difference between groups in rash improvement (medical practitioner-rated) in favour of acyclovir versus all comparators (RR 2.45, 95% CI 1.33 to 4.53; 3 studies, 141 participants). Based on the same three studies, there were no serious adverse events in either group, and there was probably no difference between groups in minor adverse events (only one participant in the placebo group experienced abdominal pain and diarrhoea). One trial compared acyclovir added to standard care (calamine lotion and oral cetirizine) versus standard care alone (24 participants). The addition of acyclovir may lead to increased itch resolution (RR 4.50, 95% CI 1.22 to 16.62) and reduction in itch score (MD 1.26, 95% CI 0.74 to 1.78) compared to standard care alone. Rash improvement (medical practitioner-rated) was not measured. The trial reported no serious adverse events in either group, and there may be no difference between groups in minor adverse events, such as headache (RR 7.00, 95% CI 0.40 to 122.44) (all results based on low-quality evidence).

AUTHORS' CONCLUSIONS

When compared with placebo or no treatment, oral acyclovir probably leads to increased good or excellent, medical practitioner-rated rash improvement. However, evidence for the effect of acyclovir on itch was inconclusive. We found low- to moderate-quality evidence that erythromycin probably reduces itch more than placebo. Small study sizes, heterogeneity, and bias in blinding and selective reporting limited our conclusions. Further research is needed to investigate different dose regimens of acyclovir and the effect of antivirals on pityriasis rosea.

Pityriasis rosea and other infectious eruptions during pregnancy: Possible life-threatening health conditions for the fetus

Any infectious illness presenting with an eruption in a pregnant patient may be associated with an increased risk of fetal loss. The viruses that can infect the placenta during maternal infection and can be transmitted to the fetus and cause congenital disease include the rubella virus, the measles virus, the varicella zoster virus, parvovirus B19, human cytomegalovirus, arboviruses, and hepatitis E virus type 1. In addition, some bacteria responsible for exanthematous diseases, like Treponema pallidum, can be transmitted during pregnancy from the mother to the fetus and cause fetal loss. All these infectious agents can cause typical and/or atypical exanthems whose etiologic diagnosis is sometimes difficult but important to determine, especially in pregnant women because of the potential risk to the fetus. In the last 20 years, we have extensively studied pityriasis rosea from the clinical and laboratory perspectives, demonstrating the pathogenic role of human herpesvirus (HHV)-6 and -7. We synthesize the available evidence that PR may be associated with active HHV-6/7 infection and therefore with complications during pregnancy and fetal loss. We have also summarized the emerging infectious illnesses of dermatologic interest that may represent life-threatening health conditions for the fetus: measles, rubella, arbovirus infection, and syphilis.

Pityriasis Rosea: An Update on Etiopathogenesis and Management of Difficult Aspects

Pityriasis rosea (PR) is a benign papulosquamous disorder seen commonly in clinical practice. Despite its prevalence and benign nature, there are still times when this common disorder presents in an uncommon way or course posing diagnostic or management problems for the treating physician. The etiopathogenesis of PR has always been a dilemma, and extensive research is going on to elicit the exact cause. This review focuses mainly on the difficult aspects of this benign common disorder such as etiopathogenesis, atypical manifestations, recurrent cases, differential diagnosis, therapy and pregnancy considerations. Although we could not find a black and white solution to all these problems, we have tried to compile the related literature to draw out some conclusions.

Pityriasis rosea of Gibert: immunological aspects

More than 200 years after first description and 150 years after complete definition by Gibert, pityriasis rosea (PR) is still a clinical entity with many obscure aspects. Although great interest was focused on aetiology, studies on immunological mechanisms associated with this disease were rather discontinuous. We present a review of the literature on immunological features of PR, aimed to outline a unified picture of currently available knowledge in this field and create a useful starting point for future research.

Pityriasis rosea and herpesviruses: facts and controversies

Pityriasis rosea is an acute exanthem with many clinical and epidemiologic features of an infectious disease. To date, human herpesvirus (HHV)-6 and HHV-7 appear to be the most indicted culprits, and the evidence in favor of this hypothesis and the controversial results produced elsewhere are discussed. The complex pathophysiology of HHV-6 and HHV-7 infection, their diffusion in the population at large, the difficulties of understanding whether the infection is still latent or is clinically manifest, and well as whether pityriasis rosea depends on a reinfection or on a viral reactivation, all make the issue extremely difficult to study and understand.

Pityriasis rosea: an update with a critical appraisal of its possible herpesviral etiology

Pityriasis rosea is an acute, self-healing exanthem characterized by oval erythematous-squamous lesions of the trunk and limbs, that usually spares face, scalp, palms, and soles. Constitutional symptoms, which have the character of true prodromes; clinical features, which resemble those of the known exanthems; and many epidemiologic data all suggest an infectious origin. A host of infectious agents have been incriminated, but, recently, human herpesvirus 6 and 7 have been extensively studied. The goal of this review is to outline the epidemiologic, clinical, histologic, and ultrastructural features of pityriasis rosea, but mainly to stress its possible human herpesvirus nature. In addition, clues have been added to help the reader to go through the complex subtleties of the virologic investigation.

Characterization of the inflammatory cell infiltrate in herald patches and fully developed eruptions of pityriasis rosea

BACKGROUND

Pityriasis rosea (PR) is a common cutaneous papulosquamous disorder affecting young adults. Previous studies have suggested possibilities of a viral aetiology and the involvement of cell-mediated immunity, but these remain unproven to date.

AIM

To elucidate the possible pathomechanisms in PR by characterizing the inflammatory cellular infiltrate in herald patches and fully developed PR eruptions.

METHODS

In total, 12 biopsy specimens from 6 patients diagnosed with PR were examined. For each patient, biopsies were taken from both a herald patch and a secondary patch. Specimens were processed for histopathological examination and immunohistochemical staining with a large panel of monoclonal antibodies.

RESULTS

Histopathologically, all specimens showed epidermal changes such as parakeratosis, orthokeratosis, epidermal hyperplasia and spongiosis. Less common results included epidermal exocytosis and focal parakeratosis. In all biopsies, the dermal infiltrate of lymphocytes stained positively for monoclonal antibodies specific for T cells. The ratio of the CD4+ (helper) vs. CD8+ (cytotoxic) T cells in the dermal infiltrate was increased in most specimens. Increased staining for Langerhans cells was seen within the dermis of lesional skin. There were no marked differences found in histopathology and immunohistochemistry between the herald patch and secondary lesions. Overall, there was a lack of natural killer cell and B-cell activities in PR lesions.

CONCLUSIONS

Our results support a predominantly T-cell mediated immunity in the development of PR.

The role of human herpesvirus 6, human herpesvirus 7, Epstein-Barr virus and cytomegalovirus in the aetiology of pityriasis rosea

AIM

To identify the role of human herpesvirus 6 (HHV-6), HHV-7, Epstein-Barr virus (EBV) and cytomegalovirus (CMV) in the pathogenesis of pityriasis rosea (PR).

MATERIAL

Polymerase chain reaction with specific primers for HHV-6 and HHV-7 DNA sequences was performed on the blood and tissue samples of 25 patients with PR and on the blood samples of age- and sex-matched healthy controls. HHV-6, EBV, CMV immunoglobulin M (IgM) and IgG were analysed by enzyme-linked immunosorbent assay, HHV-7 IgM and IgG were analysed by indirect immunofluorescence on the serum samples of the study population. In the patient group, the values were studied 2 weeks later again (second control).

RESULTS

There were no differences between the first and second controls of the patients and healthy subjects regarding HHV-6 IgM, HHV-7 IgM, CMV IgM, EBV IgM results. There were significant differences between the first [HHV-6 DNA (2 of 25), HHV-7 DNA (6 of 25)] and second control [HHV-6 DNA (1 of 25), HHV-7 DNA (11 of 25)] of the patients for the blood samples in favour of HHV-7. PR patients showed higher amounts of HHV-6 and HHV-7 DNA positivity when compared with that of healthy subjects. HHV-7 seemed to be more important regarding tissue samples [HHV-6 DNA (7 of 25), HHV-7 DNA (12 of 25) first control, HHV-6 DNA (6 of 25), HHV-7 DNA (12 of 25) second control] as well as blood samples.

CONCLUSION

Though our results failed to support a causal relationship among EBV, CMV and PR, they indicated a possible role for HHV-6 and especially HHV-7 in a group of Turkish patients but other aetiological factors may exist.

Interventions for pityriasis rosea

BACKGROUND

Pityriasis rosea is a scaly rash that mainly affects young adults. It can be very itchy but most people recover within 2 to 12 weeks.

OBJECTIVES

To assess the effects of interventions for pityriasis rosea.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (December 2004), the Cochrane Central Register of Controlled Clinical Trials in The Cochrane Library (Issue 4, 2004), MEDLINE (1966 to January 2005), EMBASE (1976 to January 2005), LILACS (1982 to January 2005), BIOSIS Preview (1980 to June 2002), and ongoing trials databases. We scanned bibliographies of published studies, abstracts from dermatology conference proceedings, corresponded with trialists and contacted the pharmaceutical industry.

SELECTION CRITERIA

Randomised controlled trials evaluating interventions for pityriasis rosea.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed trial quality and extracted data. We contacted study authors to retrieve missing data.

MAIN RESULTS

Three trials involving 148 people were included. One poor quality trial (23 people), compared intravenous glycyrrhizin and intravenous procaine. It found no significant difference between the two interventions for treating symptoms and rash. One fair quality trial (85 people), compared the oral antihistamine dexchlorpheniramine (4 mg), the oral steroid betamethasone (500 mcg), and a combination of betamethasone (250 mcg) and dexchlorpheniramine (2 mg). It found no significant difference in itch resolution at two weeks, as rated by the participants, between dexchlorpheniramine and betamethasone, and the combination of dexchlorpheniramine and betamethasone. However, both dexchlorpheniramine and betamethasone alone seem to be better at clearing rash than the combination of dexchlorpheniramine and betamethasone. These interventions were not compared with placebo. The small good quality trial (40 people) that compared oral erythromycin and placebo found that erythromycin was more effective than placebo in terms of rash improvement, as rated by the trialists, after two weeks (RR 13.00; 95% CI 1.91 to 88.64). It was also more effective in decreasing the itch score (difference of 3.95 points, 95% CI 3.37 to 4.53). No serious adverse effects were reported for the interventions. Two out of 17 people on oral erythromycin and 1 out of 17 on placebo reported minor gastrointestinal upset.

AUTHORS' CONCLUSIONS

We found inadequate evidence for efficacy for most treatments for pityriasis rosea. Oral erythromycin may be effective in treating the rash and decreasing the itch. However, this result should be treated with caution since it comes from only one small RCT. More research is necessary to evaluate the efficacy of erythromycin and other treatments.

The detection of human herpesvirus-8 DNA in plasma and peripheral blood mononuclear cells in adult patients with pityriasis rosea by polymerase chain reaction

BACKGROUND

Herpesvirus-like particles have been reported to be detectable by electron microscopy in lesional biopsy of patients with pityriasis rosea (PR). We report a study investigating the association of PR with human herpesvirus-8 (HHV-8) infection.

METHODS

Our setting is a teaching clinic affiliated to a university. We recruited eight patients aged 28-47 years (mean: 34.5 years) diagnosed with PR during a one-year period. We collected acute blood specimens at presentation and convalescent blood specimens three to four weeks later. We also collected skin scrapings from the herald patch where present and from truncal secondary lesions.

RESULTS

We detected HHV-8 DNA by a nested PCR (polymerase chain reaction) targeting, respectively, a 233-bp and a 160-bp fragment of ORF 26. PCR for HHV-8 DNA was negative in the peripheral blood mononuclear cells and plasma of acute and convalescent specimens of all patients, and negative in all skin scrapings. We detected anti-HHV-8 IgG and IgM antibodies by the indirect immunofluorescence. Four patients had IgG antibodies against HHV-8, but with no significant rise of titre. None were positive for anti-HHV-8 IgM antibody.

CONCLUSION

We conclude that PR is not associated with HHV-8 infection.

Differential tropism of human herpesvirus 6 (HHV-6) variants and induction of latency by HHV-6A in oligodendrocytes

Human herpesvirus 6 (HHV-6) is a ubiquitous β-herpesvirus associated with a number of clinical disorders. Two closely but biologically distinct variants have been described. HHV-6 variant B causes the common childhood disease exhanthem subitum, and although the pathologic characteristics for HHV-6 variant A are less well defined, HHV-6A has been suggested to be more neurotropic. We studied the effect of both HHV-6 variants in an oligodendrocyte cell line (MO3.13). Infection of M03.13 was monitored by cytopathic effect (CPE), quantitative TaqMan PCR for viral DNA in cells and supernatant, reverse transcriptase-polymerase chain reaction (RT-PCR) to detect viral RNA, and indirect immunofluorescence (IFA) to detect viral protein expression. HHV-6A infection induced significantly more CPE than infection with HHV-6B. HHV-6B induced an abortive infection associated with a decrease of the initial viral DNA load over time, early RNA expression, and no expression of viral antigen. In contrast, infection with HHV-6A DNA persisted in cells for at least 62 days. During the acute phase of infection with HHV-6A, intracellular and extracellular viral load increased and cells expressed the viral protein IE-2 and gp116/54/64. No HHV-6A RNA or protein was expressed after 30 days post infection, suggesting that HHV-6A formed a latent infection. These studies provide in vitro support to the hypothesis that HHV-6 can actively infect oligodendrocytes. Our results suggest that HHV-6A and HHV-6B have different tropism in MO3.13 cells and that an initially active HHV-6A infection can develop latency. Differences between HHV-6A and -6B infection in different neural cell types may be associated with different neurological diseases.

Additional evidence that pityriasis rosea is associated with reactivation of human herpesvirus-6 and -7

To elucidate the role of human herpesvirus (HHV)-6 and -7 (HHV-7) in pityriasis rosea (PR), we measured their DNA load in plasma, peripheral blood mononuclear cells (PBMC), and tissues using a calibrated quantitative real-time PCR assay. We also studied HHV-6- and HHV-7-specific antigens in skin by immunohistochemistry and anti-HHV-7 neutralizing activity using a syncytia-inhibition test. Plasma and PBMC were obtained from 31 PR patients (14 children, 17 adults), 12 patients with other dermatites, and 36 blood donors. Skin biopsies were obtained from 15 adults with PR and 12 with other dermatites. HHV-6 and HHV-7 DNA were detected in 17% and in 39% of PR plasmas, respectively, but in no controls. HHV-7 viremia was associated with a higher PBMC load and, in adults, with systemic symptoms. HHV-7, but not HHV-6, levels in PBMC were higher in PR patients than in controls. HHV-6 and HHV-7 antigens were found only in PR skin (17% and 67% of patients analyzed, respectively), indicating a productive infection. Syncytia-neutralizing antibodies were found in PR patients and controls, but their titers were lower in patients with HHV-7 viremia. These data confirm the causal association between PR and active HHV-7 or, to a lesser extent, HHV-6 infection.

Investigation of herpes simplex virus DNA in pityriasis rosea by polymerase chain reaction

BACKGROUND

Pityriasis rosea (PR) is an acute, inflammatory disease of unknown cause. Clinical and experimental findings indicate an infectious etiology of PR. Our purpose is to examine the skin lesions and blood samples of PR patients by polymerase chain reaction (PCR) for the presence of HSV type 1 and 2 DNA.

METHODS

The lesional skin biopsies from 10 patients and blood samples from two randomized patients with clinically and histologically confirmed pityriasis rosea were examined by PCR.

RESULTS

No HSV 1 and HSV 2 DNA was detected in the lesional biopsy and blood samples.

CONCLUSIONS

We could not identify a relationship between HSV 1, HSV 2 and PR.

Is human herpesvirus 7 the causative agent of pityriasis rosea?--A critical review

BACKGROUND

Conflicting results on the association of pityriasis rosea and human herpesvirus 7 infection have been reported by different investigators.

AIM

To review the level of evidence for such an association.

METHODS

Medline was searched with unlimited data entry and 13 reports were retrieved. The data were analyzed for a causative association according to the criteria of Fredericks and Relman, which take into consideration latent infection and the reactivation of viruses characteristic of herpesviruses, and the roles of sequence-based detection methods.

RESULTS

None of the criteria was substantiated by the findings of most investigators. Factors leading to the discrepancies of the results were discussed.

CONCLUSION

There is currently insufficient evidence that human herpesvirus 7 infection is causally related to pityriasis rosea.

The role of human herpes virus 6 and 7 in the pathogenesis of pityriasis rosea

Pityriasis rosea (PR) is an acute exanthematous inflammatory skin disease in which many epidemiological studies suggest a viral infection in its pathogenesis. Several viruses such as picornaviruses, parvoviruses and herpes viruses were accused as causative agents in PR. Human herpes virus-6 (HHV-6) and HHV-7 are newly discovered members of herpesviridae family. Several diseases including roseola infantum and PR have been linked with HHV-6 and HHV-7 in dermatology. We aimed to investigate the role of HHV-6 and HHV-7 in the pathogenesis of PR. Blood samples from 35 patients with acute PR and 30 healthy volunteers were examined to obtain titres for HHV-6 and HHV-7 antibodies. Anti-HHV-6 and -HHV-7 immunoglobulin (Ig) G antibodies were detected by IFA. The high titres of anti-HHV-6 IgG were determined in four patients and anti-HHV-7 IgG in only two of four patients. In our study, we haven't found any significant relationship between HHV-6, HHV-7 and PR. Our results were supported with the data of several previous studies.

Pitiríase rósea purpúrica: relato de caso e revisão da literatura

A pitiríase rósea purpúrica constitui doença rara e 10 casos foram publicados na Europa e EUA. O quadro clínico cutâneo é a forma hemorrágica ou purpúrica com variável descamação marginal. Relata-se o caso de um homem de 25 anos de idade com lesões na região escapular. A revisão da literatura enfatiza o diagnóstico diferencial das lesões purpúricas. Segundo Lilacs e Medline, não foram relatados casos na literatura latino-americana.

Pityriasis rosea is associated with systemic active infection with both human herpesvirus-7 and human herpesvirus-6

Pityriasis rosea is a common skin disease that has been suspected to have a viral etiology. We performed nested polymerase chain reaction to detect human herpesvirus-7, human herpesvirus-6, and cytomegalovirus DNA in lesional skin, nonlesional skin, peripheral blood mononuclear cells, serum, and saliva samples isolated from 14 pityriasis rosea patients. Viral mRNA expression and virion visualization within lesional skin were studied by in situ hybridization and transmission electron microscopy, respectively. By nested polymerase chain reaction, human herpesvirus-7 DNA was present in lesional skin (93%), nonlesional skin (86%), saliva (100%), peripheral blood mononuclear cells (83%), and serum (100%) samples, whereas human herpesvirus-6 DNA was detected in lesional skin (86%), nonlesional skin (79%), saliva (80%), peripheral blood mononuclear cells (83%), and serum (88%) samples. By contrast, cytomegalovirus DNA was not detected in these tissues. Control samples from 12 healthy volunteers and 10 psoriasis patients demonstrated rare positivity for either human herpesvirus-7 or human herpesvirus-6 DNA in skin or serum. By in situ hybridization, infiltrating mononuclear cells expressing human herpesvirus-7 and human herpesvirus-6 mRNA were identified in perivascular and periappendageal areas in 100% and 75% pityriasis rosea skin lesions, respectively, compared to herpesviral mRNA positivity in only 13% normal skin and psoriasis skin controls. Transmission electron microscopy failed to reveal herpesviral virions in pityriasis rosea lesional skin. Nested polymerase chain reaction and in situ hybridization enabled detection of human herpesvirus-7 and human herpesvirus-6 in skin and other tissues isolated from patients with pityriasis rosea. These results suggest that pityriasis rosea is associated with systemic active infection with both human herpesvirus-7 and human herpesvirus-6.

Human herpesvirus 7 in dermatology: what role does it play?

Human herpesvirus 7 (HHV-7) was discovered in 1989 as a new member of the beta-herpesvirus subfamily. Primary infection occurs early in life and manifests as exanthema subitum, or other febrile illnesses mimicking measles and rubella. Thus, HHV-7 has to be considered as a causative agent in a variety of macular-papular rashes in children. In addition, HHV-7 was found in some cases of other inflammatory skin disorders, such as psoriasis. There are controversial data on the detection of HHV-7 in pityriasis rosea, but so far there is not enough evidence for a pathogenetic association of HHV-7 with this exanthematic skin disease. Although HHV-7 can be found in some cases of Hodgkin's disease, there are no data supporting a direct causative role in this lymphoma type nor in other nodal or primary cutaneous lymphomas. In various epidemiologic forms of Kaposi's sarcoma, infection of monocytic cells with HHV-7 was demonstrated, which may indirectly influence tumor biology. In the context of immunosuppression, HHV-7 has recently been identified as an emerging pathogen in transplant recipients and may exacerbate graft rejection in renal transplant recipients. The ability of HHV-7 to induce cytokine production in infected cells could make HHV-7 an important pathogenetic co-factor in inflammatory and neoplastic disorders. Moreover, the restricted cellular tropism of HHV-7 may render this virus an interesting vector for gene therapy. Thirteen years after the discovery of HHV-7, there has been considerable progress in characterizing its genetic structure, virus-induced effects on infected host cells and in the development of diagnostic tools. Nevertheless, the role of HHV-7 in various skin diseases and the clinical manifestations of reactivation of HHV-7 infection have still to be defined.

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

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 specimens 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.

Localized pityriasis rosea

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.

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

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.

Update on selected viral exanthems

Viral exanthems are common in childhood and account for a large number of patient visits to pediatric or family medicine clinics. Most exanthems are virtually harmless to the healthy child, but others can be signs of more significant systemic disease. Some exanthems that are benign or self-limited in the healthy child may propose significant risk to pregnant or immunocompromised individuals. Therefore, recognition of exanthems, which may be associated with certain viral illnesses, is important for the primary care provider. For example, prompt recognition of a viral exanthem caused by parvovirus may allow a pregnant female from exposing her fetus to a potentially fatal infection, or, if the exposure has already occurred, may indicate the need for appropriate fetal monitoring. In this manuscript, we review the recent literature pertaining to four characteristic exanthems that are thought to be viral in nature: papular purpuric gloves and socks syndrome; pityriasis rosea; unilateral lateral thoracic exanthem; and Gianotti-Crosti syndrome.