Case clustering in pityriasis rosea: support for role of an infective agent

Overlapping Signs and Symptoms Between Recurrent Varicella and Pityriasis rosea Gibert

BACKGROUND

Pityriasis rosea Gibert (PRG) has features similar to those of common infectious childhood diseases, suggesting a viral cause, but no agent has been identified to date. We describe 4 children with PRG and 2 with recurrent varicella who were studied using photochronography, virology and immunology.

METHODS

The 6 patients with skin rashes visited our pediatric clinic from April 2012 to May 2016. Photographs of their skin lesions were taken; blood, skin lesions, and/or nasal lavage samples were collected to detect varicella-zoster virus (VZV) DNA and antibodies; and skin tests were carried out to measure cell-mediated immunity to VZV.

RESULTS

Herald patches were confirmed in 2 of 4 PRG patients. No specimen cultures were positive for infectious VZV. However, VZV-DNA was detected in skin lesions of 3 PRG patients. During the acute phase, 5 patients had IgG antibodies to VZV, and skin-test reactions were positive in 5 patients.

CONCLUSIONS

IgG antibody titers to VZV at rash onset were high, suggesting that they were already rising at the appearance of the rash and that reinfection with VZV must have occurred during the prodromal stage or several weeks before rash appearance in PRG patients whose immunity had declined below the threshold. Our study suggests a new pathogenesis of PRG that might help to address incongruities of past theories on PRG sites of viral entry and replication, incubation period and variations in the clinical course of PRG from prodrome to healing.

Pityriasis rosea in pregnancy: A case series and literature review

Background and objective

Pityriasis rosea (PR), a common skin disease in young adults, may adversely affects the course of pregnancy and the unborn child.

Patients and methods

Data from forty‐six pregnant women with PR seen in the dermatological university clinic between 2003 and 2018 were analyzed and compared with patient data (n = 53) from previously published studies to determine the incidence and risk factors for an unfavorable pregnancy outcome after PR infection.

Results

Unfavorable pregnancy outcomes (defined as miscarriage, preterm delivery before week 37 of gestation, or birth weight < 2,500 g) were significantly less frequent in our study population than in a pooled cohort obtained from previously published studies (10.9 % vs. 39.6 %; P = 0.0012). Analysis of pooled data from our study and from previous studies revealed that the week of pregnancy at onset of PR was inversely associated with an unfavorable outcome (odds ratio [OR] = 0.937; 95 % CI 0.883 to 0.993). In addition, duration of PR (OR = 1.432; 95 % CI 1.129 to 1.827), additional extracutaneous symptoms (OR = 4.112; 95 % CI 1.580 to 10.23), and widespread rash distribution (OR 5.203, 95 % CI 1.702 to 14.89) were directly associated with unfavorable outcome.

Conclusion

In most cases, PR does not influence pregnancy or birth outcomes.

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, Gianotti-Crosti Syndrome, Asymmetric Periflexural Exanthem, Papular-Purpuric Gloves and Socks Syndrome, Eruptive Pseudoangiomatosis, and Eruptive Hypomelanosis: Do Their Epidemiological Data Substantiate Infectious Etiologies?

Many clinical and laboratory-based studies have been reported for skin rashes which may be due to viral infections, namely pityriasis rosea (PR), Gianotti-Crosti syndrome (GCS), asymmetric periflexural exanthem/unilateral laterothoracic exanthem (APE/ULE), papular-purpuric gloves and socks syndrome (PPGSS), and eruptive pseudo-angiomatosis (EP). Eruptive hypomelanosis (EH) is a newly discovered paraviral rash. Novel tools are now available to investigate the epidemiology of these rashes. To retrieve epidemiological data of these exanthema and analyze whether such substantiates or refutes infectious etiologies. We searched for articles published over the last 60 years and indexed by PubMed database. We then analyzed them for universality, demography, concurrent patients, temporal and spatial-temporal clustering, mini-epidemics, epidemics, and other clinical and geographical associations. Based on our criteria, we selected 55, 60, 29, 36, 20, and 4 articles for PR, GCS, APE/ULE, PPGSS, EP, and EH respectively. Universality or multiple-continental reports are found for all exanthema except EH. The ages of patients are compatible with infectious causes for PR, GCS, APE/ULE, and EH. Concurrent patients are reported for all. Significant patient clustering is demonstrated for PR and GCS. Mini-epidemics and epidemics have been reported for GCS, EP, and EH. The current epidemiological data supports, to a moderate extent, that PR, GCS, and APE could be caused by infectious agents. Support for PPGSS is marginal. Epidemiological evidences for infectious origins for EP and EH are inadequate. There might be growing epidemiological evidence to substantiate or to refute our findings in the future.

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.

A Randomized, Double-blind, Placebo-Controlled Study of Efficacy of Oral Acyclovir in the Treatment of Pityriasis Rosea

BACKGROUND

Pityriasis rosea is an acute self-limiting skin disorder of unknown aetiology. Recently human herpes virus 6 and 7 has been hypothesized to be the cause of pityriasis rosea.

OBJECTIVE

To determine the efficacy of acyclovir, an anti-viral drug, in the treatment of pityriasis rosea.

MATERIALS AND METHODS

A randomized, double-blind, placebo-controlled study of efficacy of oral acyclovir in the treatment of pityriasis rosea was conducted on 73 patients. Thirty eight randomly selected patients were started on oral acyclovir. Thirty-five patients were prescribed placebo. The patients as well as the chief investigator were unaware of the therapeutic group to which patients belonged (acyclovir or placebo). Patients in both the groups were evaluated clinically after 7 and 14 days following the first visit and the data were analysed.

RESULTS

Follow up data of 60 patients was available and these were included in the statistical analysis. 53.33% and 86.66% of the patients belonging to the acyclovir group showed complete resolution on the 7(th) day and 14(th) day respectively following the first visit compared to 10% and 33.33% of patients from the placebo group. The findings were statistically significant.

CONCLUSION

The study showed that high dose acyclovir is effective in the treatment of pityriasis rosea.

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 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.

Study of role of streptococcal throat infection in pityriasis rosea

Background:

Pityriasis rosea is a common, acute exanthem of uncertain etiology. The exact cause of pityriasis rosea is not known but various hypotheses have been postulated incriminating infective agents such as viruses, bacteria, spirochete and noninfective etiologies such as atopy and autoimmune causes have also been investigated.

Aim:

We undertook a study to investigate the role of Streptococcus haemolyticus in the causation of pityriasis rosea and study the levels of C-reactive protein (CRP) and ASLO titer in patients with pityriasis rosea.

Materials and Methods:

The study included 20 patients with pityriasis rosea attending the outpatient dermatology department at JIPMER hospital during the period from June to December 2004. Corresponding number of age- and sex-matched controls were chosen from amongst healthy individuals and patients attending skin OPD with dermatological disorders other than pityriasis rosea.

Results:

On analyzing the data collected from 20 cases of pityriasis rosea, the average age was found to be 15.3 years and ranged from 5 years to 30 years. The male to female ratio was found to be 1.5:1. The average duration of illness was 14.5 days (median) and 29.3 days (mean). CRP was negative in all the cases as well as the controls. ASLO titer was found to be raised in 2 (10%) cases, while it remained below the critical value in all the controls. On comparing the cases and controls, the raised ASLO titer in the cases was found to be not statistically significant (p = 0.147). From the throat swab culture, Streptococcus haemolyticus was isolated from only one case and none of the controls. This finding was not statistically significant (p = 0.310).

Conclusion:

As per the findings of the present study, we arrived at conclusion that there is no association between streptococcus pharyngitis and pityriasis rosea.

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.

Pitiríase rósea

Pitiríase rósea é doença inflamatória aguda da pele, que regride espontaneamente, normalmente sem deixar seqüelas, em período que varia de quatro a oito semanas. Clinicamente é caracterizada pelo aparecimento de típicas lesões eritêmato-pápulo-escamosas. Atinge todas as idades, embora seja mais comumente observada entre 10 e 35 anos. Apesar de exaustivas pesquisas, sua etiologia ainda permanece desconhecida. São discutidos alguns aspectos epidemiológicos, anatomoclínicos, diagnósticos diferenciais, doenças associadas, com ênfase no tratamento e etiologia da doença.

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.

Effect on quality of life in patients with pityriasis rosea: Is it associated with rash severity?

BACKGROUND

It is unknown how the quality of life (QOL) is affected in patients with pityriasis rosea (PR), and whether it is related to rash severity.

METHODS

We constructed a valid and reliable Cantonese version of the Dermatology Life Quality Index (DLQI). We recruited patients with PR, with atopic dermatitis and with acne vulgaris, and controls of the same sex and comparable age. We applied the DLQI and the Pityriasis Rosea Severity Score (PRSS) to the patients with PR, the DLQI and the SCORing Atopic Dermatitis Index (SCORAD) to the controls with atopic dermatitis, and the DLQI and the Leeds Acne Grading System (LAGS) to the controls with acne vulgaris.

RESULTS

Total DLQI scores of the 22 patients with PR (mean: 6.36, SD: 5.79) were significantly lower than those of the 22 controls with atopic dermatitis (mean: 12.00, SD: 5.38) (P = 0.021), but were insignificantly different from those of the 22 controls with acne vulgaris (mean: 6.86, SD: 4.53) (P = 0.57). Correlation between the total DLQI and PRSS scores was weak (gamma(s) = +0.19) and insignificant (P = 0.40). All six DLQI parameters were insignificantly correlated with the PRSS scores. In contrast, the total DLQI scores and most of the DLQI parameters were strongly correlated with the rash severity scores for the control subjects. Significantly more patients with PR have concerns regarding disease etiology and infectivity.

CONCLUSIONS

The QOL of the patients with PR was significantly less affected than that for the patients with atopic dermatitis, but was insignificantly different from the patients with acne vulgaris. Unlike atopic dermatitis and acne vulgaris, the effects on the QOL in PR are insignificantly correlated with rash severity. These results bear important implications on clinical management.

Pityriasis rosea. Appearance and distribution of macules aid diagnosis

A 40-year-old man presented with a 1-week history of a diffuse pruritic rash. The patient denied having had fever, chills, or a recent respiratory infection. He could not recall having an initial patch. Physical examination revealed numerous small, scaly patches on his trunk (figure 1). The rash spared the palms of his hands and soles of his feet as well as the distal extremities.

Pityriasis rosea Gibert: detection of Legionella micdadei antibodies in patients

Some epidemiological and clinical characteristics of Pityriasis rosea Gibert has led us to hypothesize that this disease may be the clinical manifestation of an infection caused by legionellas. We have thus tested the sera of 36 patients ill with Pityriasis rosea and 19 controls for Legionella pneumophila serogroup 1-6 and Legionella micdadei antibodies. These, who had the same age and sex distribution as study patients, were receiving treatment for other diseases in the same ward. Also tested were 200 sera from the voluntary blood donors from the same region as study patients. Legionella micdadei antibodies were detected in 12 (33.3%) Pityriasis rosea cases and in one (5.2%) control. They were significantly more common in Pityriasis rosea cases than in either controls or voluntary blood donor population. The findings to date encourage continued research into the causative relationship between the Legionella micddadei infection and the onset of Pityriasis rosea Gibert.

Does infection initiate Graves disease? A population based 10 year study

In order to detect whether micro-organisms could initiate the autoimmune process in Graves' disease we have studied the temporal and spatial distribution of 857 cases of hyperthyroidism occurring in a community over ten years. Cases were identified through biochemistry laboratory records and following the exclusion of patients with toxic nodular goitre or with insufficient clinical data there were 599 with Graves' disease--an average annual incidence of 15.9 per 100,000. There was a tendency for cases to present in the summer months. The reported onset of symptoms, however, peaked in December and June. There was no evidence of clustering of cases in space and time using two different statistical methods. Incidence rates doubled between 1976 and 1980 and then declined--a trend that could neither be explained by changes in laboratory or clinical diagnosis nor did it correlate with any pattern of microbial disease in the area. We conclude that it is unlikely that infections that behave in an epidemic manner have a causative role in triggering Graves' disease.

Pityriasis rosea update: 1986

Pityriasis rosea is a common self-limited dermatologic disorder. It appears to be a nonspecific cutaneous reaction pattern with a large number of causes. Current evidence indicates that a cell-mediated immune mechanism may be important in its pathogenesis.

A point-source asthma outbreak

Epidemiological data for the eighth asthma epidemic in Barcelona were available from the whole city. They reveal a striking space clustering, an hour-time clustering, and simultaneous time and space clustering, which indicate that the outbreak was a point-source epidemic. Air pollution by smoke and oxides of sulphur and nitrogen was unlikely to have been the cause of the epidemic, as was an unusual level of pollen or fungal spores. The industrial area adjacent to the neighbourhood in which the epidemic occurred was a probable source of the cause of the outbreak.

Papulosquamous diseases: a review

Papulosquamous diseases are a heterogeneous group of disorders whose etiology primarily is unknown. The nosology of these disorders is based on a descriptive morphology of clinical lesions characterized by scaly papules and plaques. The major entities in this group include psoriasis, parapsoriasis (including pityriasis lichenoides et varioliformis acuta), lichen planus, lichen nitidus, lichen striatus, pityriasis rosea, pityriasis rubra pilaris, seborrheic dermatitis, and the Gianotti-Crosti syndrome. Many other conditions may become papulosquamous and should be considered in the differential diagnosis.

Recent upper respiratory tract infection and pityriasis rosea: a case-control study of 249 matched pairs

A sample of 249 patients was drawn from an original population of 939 patients with pityriasis rosea identified in an earlier population-based study of pityriasis rosea in Rochester, Minnesota. A control was selected for each case, matched for age, sex, and year of diagnosis. Comparison was made with regard to recent immunization, history of atopy, and recent infection. A statistically significant number of patients had experienced recent upper respiratory tract infection (P less than 0.005). The association between recent infection and pityriasis rosea is discussed.

Detection of minimal epidemics

Epidemiologists seeking epidemics of events in time, and attempting to distinguish real epidemics from random clusters, need to calculate the random probability of n or more events occurring within a time window of duration w, and for any position of the window as it scans continuously across the period of observation. Exact algebraic solutions have been proposed by other workers, but, over a wide range of important values, systematic arithmetic evaluation is beyond the capacity of existing computers. This paper proposes an approximate test which is quick and simple and which achieves the same purpose. An example of its application is given.