Update on selected viral exanthems

Disorders characterized by predominant or exclusive dermal inflammation

Some cutaneous inflammatory disorders are typified by a predominant or exclusive localization in the dermis. They can be further subdivided by the principal cell types into lymphocytic, neutrophilic, and eosinophilic infiltrates, and mixtures of them are also seen in a proportion of cases. This review considers such conditions. Included among the lymphoid lesions are viral exanthems, pigmented purpuras, gyrate erythemas, polymorphous light eruption, lupus tumidus, and cutaneous lymphoid hyperplasia. Neutrophilic infiltrates are represented by infections, Sweet syndrome, pyoderma gangrenosum, and hidradenitis suppurativa, as well as a group of so-called "autoinflammatory" dermatitides comprising polymorphonuclear leukocytes. Eosinophil-dominated lesions include arthropod bite reactions, cutaneous parasitic infestations, the urticarial phase of bullous pemphigoid, Wells syndrome (eosinophilic cellulitis), hypereosinophilic syndrome, and Churg-Strauss disease. In other conditions, eosinophils are admixed with neutrophils in the corium, with or without small-vessel vasculitis. Exemplary disorders with those patterns include drug eruptions, chronic idiopathic urticaria, urticarial vasculitis, granuloma faciale, and Schnitzler syndrome (chronic urticarial with a monoclonal gammopathy).

Gianotti-Crosti syndrome, pityriasis rosea, asymmetrical periflexural exanthem, unilateral mediothoracic exanthem, eruptive pseudoangiomatosis, and papular-purpuric gloves and socks syndrome: a brief review and arguments for diagnostic criteria

Several exanthems including Gianotti-Crosti syndrome, pityriasis rosea, asymmetrical periflexural exanthem, eruptive pseudoangiomatosis, and papular-purpuric gloves and socks syndrome are suspected to be caused by viruses. These viruses are potentially dangerous. Gianotti-Crosti syndrome is related to hepatitis B virus infection which is the commonest cause of hepatocellular carcinoma, and Epstein-Barr virus infection which is related to nasopharyngeal carcinoma. Pityriasis rosea has been suspected to be related to human herpesvirus 7 and 8 infections, with the significance of the former still largely unknown, and the latter being a known cause of Kaposi's sarcoma. Papular-purpuric gloves and socks syndrome is significantly associated with human B19 erythrovirus infection which can lead to aplastic anemia in individuals with congenital hemoglobinopathies, and when transmitted to pregnant women, can cause spontaneous abortions and congenital anomalies. With viral DNA sequence detection technologies, false positive results are common. We can no longer apply Koch's postulates to establish cause-effect relationships. Biological properties of some viruses including lifelong latent infection, asymptomatic shedding, and endogenous reactivation render virological results on various body tissues difficult to interpret. We might not be able to confirm or refute viral causes for these rashes in the near future. Owing to the relatively small number of patients, virological and epidemiology studies, and treatment trials usually recruit few study and control subjects. This leads to low statistical powers and thus results have little clinical significance. Moreover, studies with few patients are less likely to be accepted by mainstream dermatology journals, leading to publication bias. Aggregation of data by meta-analyses on many studies each with a small number of patients can theoretically elevate the power of the results. Techniques are also in place to compensate for publication bias. However, these are not currently feasible owing to different inclusion and exclusion criteria in clinical studies and treatment trials. The diagnoses of these rashes are based on clinical assessment. Investigations only serve to exclude important differential diagnoses. A wide spectrum of clinical features is seen, and clinical features can vary across different populations. The terminologies used to define these rashes are confusing, and even more so are the atypical forms and variants. Previously reported virological and epidemiological results for these rashes are conflicting in many aspects. The cause of such incongruence is unknown, but low homogeneity during diagnosis and subject recruitment might be one of the factors leading to these incongruent results. The establishment and proper validation of diagnostic criteria will facilitate clinical diagnosis, hasten recruitment into clinical studies, and allow results of different studies to be directly compared with each another. Meta-analyses and systematic reviews would be more valid. Diagnostic criteria also streamline clinical audits and surveillance of these diseases from community perspectives. However, over-dependence on diagnostic criteria in the face of conflicting clinical features is a potential pitfall. Clinical acumen and the experience of the clinicians cannot be replaced by diagnostic criteria. Diagnostic criteria should be validated and re-validated in response to the ever-changing manifestations of these intriguing rashes. We advocate the establishment and validation of diagnostic criteria of these rashes. We also encourage the ongoing conduction of studies with a small number of patients. However, for a wider purpose, these studies should recruit homogenous patient groups with a view towards future data aggregation.

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.

Echovírus 6 associado à doença exantemática

Exantema viral é considerado problema comum em regiões tropicais, afetando principalmente crianças. Diversos exantemas cutâneos estão associados a infecções por Enterovirus. Amostras biológicas provenientes de uma criança apresentando exantema generalizado foram enviadas ao Laboratório de Vírus Entéricos do Instituto Adolfo Lutz para a realização do diagnóstico laboratorial. Amostra viral isolada em RD (human rhabdomyosarcoma cells) foi submetida à reação em cadeia pela polimerase apresentando um produto de 437 pares de base, característico de gênero Enterovirus. O sorotipo echovirus 6 (E-6) foi identificado por ensaio de imunofluorescência indireta. Em adição, as amostras pareadas de soro apresentaram soroconversão para E-6. Até o momento, não há relatos do envolvimento de E-6 associado a doenças exantemáticas no Brasil, enfatizando a importância da vigilância epidemiológica para essas doenças e suas complicações.

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.

Viral exanthems in the tropics

Viral exanthems are a common problem in tropical regions, particularly affecting children. Most exanthems are transient and harmless, but some are potentially very dangerous. Pregnant women and malnourished or immunocompromised infants carry the greatest risk of adverse outcome. In this article, parvovirus B19; dengue and yellow fever; West Nile, Barmah Forest, Marburg, and Ebola viruses, and human herpesviruses; asymmetric periflexural exanthema of childhood; measles; rubella; enteroviruses; Lassa fever; and South American hemorrhagic fevers will be discussed.

Childhood viral exanthems

Many viral infections exhibit cutaneous lesions. Recognition of the exanthems associated with these infections and the broader clinical scenarios in which they occur can lead to more rapid diagnosis and appropriate treatment for affected patients.

Petechial exanthem in "bathing trunk" distribution caused by parvovirus B19 infection

We report a 13-year-old boy with a petechial rash on the genital area, in which primary infection by Parvovirus B19 was demonstrated by seroconversion. To our knowledge this is the first instance of an exanthem arising from Parvovirus B19 with an exclusive genital distribution without typical acral involvement.

New and emerging pediatric infections

Several aspects of emerging pediatric cutaneous infections are of importance to the clinician. New manifestations of parvovirus infection should be recognized promptly, especially because transmission to susceptible populations might lead to serious complications. In the immunocompromised pediatric population, the outcome of cutaneous mold infections can be improved with prompt recognition and initiation of treatment. The incidence of community-acquired MRSA infections in pediatrics is becoming more than a regional concern, and this coincides with the issue of limited antibiotic susceptibility for MRSA as well as other infections. New antibiotics such as linezolid are emerging as potential treatments for drug-resistant pathogens. An older group of antibiotics, the fluoroquinolones, appear to be well tolerated in children and should not be withheld from this population when the benefits of treatment out-weigh the risks.

Papular-purpuric "gloves and socks" syndrome caused by parvovirus B19

This paper presents a 15-year-old boy with an acute febrile illness accompanied by purpuric and papular lesions located mostly on the dorsal areas of his hands and feet with the additional changes on his knees and elbows. Serologic studies confirmed the acute infection by parvovirus B19. Apart from mild leukocytosis there were no other abnormalities in hematologic and laboratory findings. The diagnosis of papular-purpuric "gloves and socks" syndrome (PPGSS) was made. Cutaneous changes completely resolved two weeks later. Herein the patient's condition was described together with a brief overview of the PPGSS literature concerning this relatively rare viral exanthema.

Parvovirus B19: a review

Infection with parvovirus B19 may result in a wide range of dermatologic manifestations. The specific skin findings include erythema infectiosum and papular purpuric "gloves-and-socks" syndrome. The nonspecific findings include reticular erythema, maculopapular eruptions, and petechiae and purpura, as well as other less frequently described findings. Associations with other dermatologic diseases, such as erythema multiforme and erythema nodosum, also have been described. A role in the pathogenesis of various collagen vascular disorders has been suggested and is under investigation. The diagnosis of infection rests on the typical clinical findings. Whenever parvovirus B19 infection is diagnosed, the physician must ensure that neither the patient nor his or her contacts is a member of certain vulnerable populations. In these populations, infection with parvovirus B19 may result in devastating complications. The vulnerable populations include those with hematologic disease, immunosuppressed patients, and pregnant women. Treatment of infection in the healthy immunocompetent individual is asymptomatic, and the acute infections typically resolve without complications.