Molluscum contagiosum

A Vocal Cord Polyp: An Atypical Case of Molluscum Contagiosum

A 44-year-old patient presented with hoarseness of voice and a polypoidal lesion on the left vocal cord. Complete excision was done. To our knowledge, this is the second reported case of molluscum contagiosum of the vocal cords. It should be considered as a differential diagnosis of a vocal cord lesion.

Molluscum Contagiosum Virus: Biology and Immune Response

Molluscum contagiosum virus is a poxvirus belonging to the Poxviridae family, which includes Orthopoxvirus, Parapoxvirus, Yantapoxvirus, Molluscipoxvirus, Smallpox virus, Cowpox virus and Monkeypox virus. MCV belongs to the genus Molluscipoxvirus and has a tropism for skin tissue. MCV infects keratinocytes and, after an incubation period of 2 weeks to 6 weeks, causes a breakdown of the skin barrier with the development of papules of variable size depending on the proper functioning of the immune response (both adaptive and acquired). MCV only infects humans and does not cause viraemia. MCV encodes for several inhibitory proteins responsible to circumvent the immune response through different signalling pathways. Individuals who can be infected with MCV are children, immunocompromised individuals such as organ transplant recipients and Human Immunodeficiency Virus (HIV)-infected individuals. Current treatments to manage MCV-induced lesions are different and include the use of immunomodulators, which, however, do not provide an effective response.

British Association for Sexual Health and HIV national guideline for the management of Genital Molluscum in adults (2021)

This guideline offers recommendations on diagnosis, treatment regimens and health promotion principles needed for the effective management of genital molluscum, including management of the initial presentation and recurrences. The Primary focus of the guideline is on infection which affects the genital area and has a sexual mode of transmission. This is an update to the guideline previously published in this journal in 2014.

Efficacy of topical treatments for molluscum contagiosum in randomized controlled trials

Although molluscum contagiosum (MC) is a common infectious dermatosis that is self-resolving, treatment can diminish discomfort and decrease the risk of autoinoculation and infection to others, because it is transmitted through direct skin contact. This systematic review evaluates the efficacy of topical treatments for MC. A PubMed search following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines was performed to find randomized, controlled trials of MC treatment. The search yielded 129 publications, but only 15 studies published between 1994 and 2020 were found to fit the inclusion criteria. Treatment modalities included podophyllotoxin, imiquimod, sodium nitrite, myrtle leaf extract, phenol, Salatac Gel (salicylic acid with lactic acid), potassium hydroxide, cantharidin, SB206, and VP-102. Outcomes were extracted from the literature, and subsequent quality and risk of bias assessments were performed. All treatments were more efficacious than the control except cantharidin, potassium hydroxide, and imiquimod, which had varying degrees of efficacy throughout studies. Overall, studies were of sufficient quality and had low risk of bias, but they had small sample sizes and lacked adequate explanation of statistical analysis. Current first-line treatment entails mechanical methods such as cryotherapy and curettage, which may be frightening to children with MC, so the development and assessment of topical treatments allows for alternative efficacious techniques.

[Human poxvirus infections]

Poxvirus (PXV) infections are a common cause of cutaneous signs. In France, certain forms of poxvirus are frequent and benign (molluscum contagiosum), while others are rare but potentially serious (cowpox virus [CPXV]). Whereas only smallpox and molluscum contagiosum viruses have a human reservoir and are transmitted between humans, most poxvirus infections are zoonoses having only animal reservoirs. Only a small number of poxviruses are responsible for infection in humans, but the increasing number of new pets, some of which are exotic, coupled with the rapid rise in international travel are creating a greater risk of transmission of zoonotic PXV to new vectors and of spread of these diseases to new regions throughout the world. In France, molluscum contagiosum, orf and milkers' nodule give rise to numerous consultations and are well known to dermatologists. However, dermatologists must also be able to identify other parapoxviruses of similar presentation to orf; thus, CPXV and monkeypox are considered potentially emergent viruses with a high risk of epidemic and spread due to increasing international transport and the loss of the maximum protection against smallpox. Finally, despite its declared eradication, smallpox is currently being monitored because of the potential risk of reintroduction, whether accidentally or deliberately through bioterrorism.

MC159 of Molluscum Contagiosum Virus Suppresses Autophagy by Recruiting Cellular SH3BP4 via an SH3 Domain-Mediated Interaction

MC159 is a viral FLIP (FLICE inhibitory protein) encoded by the molluscum contagiosum virus (MCV) enabling MCV to evade antiviral immunity and to establish persistent infections in humans. Here, we show that MC159 contains a functional SH3 binding motif, which mediates avid and selective binding to SH3BP4, a signaling protein known to regulate endocytic trafficking and suppress cellular autophagy. The capacity to bind SH3BP4 was dispensable for regulation of NF-κB-mediated transcription and suppression of proapoptotic caspase activation but contributed to inhibition of amino acid starvation-induced autophagy by MC159. These results provide new insights into the cellular functions of MC159 and reveal SH3BP4 as a novel host cell factor targeted by a viral immune evasion protein.IMPORTANCE After the eradication of smallpox, molluscum contagiosum virus (MCV) is the only poxvirus restricted to infecting humans. MCV infection is common and causes benign skin lesions that usually resolve spontaneously but may persist for years and grow large, especially in immunocompromised individuals. While not life threatening, MCV infections pose a significant global health burden. No vaccine or specific anti-MCV therapy is available. MCV encodes several proteins that enable it to evade antiviral immunity, a notable example of which is the MC159 protein. In this study, we describe a novel mechanism of action for MC159 involving hijacking of a host cell protein called SH3BP4 to suppress autophagy, a cellular recycling mechanism important for antiviral immunity. This study contributes to our understanding of the host cell interactions of MCV and the molecular function of MC159.

A comparison of the effect of molluscum contagiosum virus MC159 and MC160 proteins on vaccinia virus virulence in intranasal and intradermal infection routes

Molluscum contagiosum virus (MCV) causes persistent, benign skin neoplasm in children and adults. MCV is refractive to growth in standard tissue culture and there is no relevant animal model of infection. Here we investigated whether another poxvirus (vaccinia virus; VACV) could be used to examine MCV immunoevasion protein properties in vivo. The MCV MC159L or MC160L genes, which encode NF-κB antagonists, were inserted into an attenuated VACV lacking an NF-κB antagonist (vΔA49), creating vMC159 and vMC160. vMC160 slightly increased vΔA49 virulence in the intranasal and intradermal routes of inoculation. vMC159 infection was less virulent than vΔA49 in both inoculation routes. vMC159-infected ear pinnae did not form lesions, but virus replication still occurred. Thus, the lack of lesions was not due to abortive virus replication. This system provides a new approach to examine MCV immunoevasion proteins within the context of a complete and complex immune system.

Efficacy and Safety of Topical Cantharidin Treatment for Molluscum Contagiosum and Warts: A Systematic Review

BACKGROUND AND OBJECTIVE

Topical cantharidin is routinely used for the treatment of molluscum contagiosum and warts. The objective of this systematic review is to assess the efficacy and safety of topical cantharidin treatment for molluscum contagiosum and warts.

METHODS

We performed a systematic review of studies assessing topical cantharidin treatment of molluscum contagiosum or warts. We searched the databases of Cochrane, EMBASE, GREAT, LILACS, MEDLINE, and Scopus. Two authors performed the study selection and data extraction.

RESULTS

Twenty studies (1958-2018) met inclusion/exclusion criteria. Twelve studies assessed warts, and eight studies assessed molluscum contagiosum. Overall, 1752 patients were included (range 0.3-62 years; specified in 15 studies). Clearance rates with topical cantharidin for molluscum contagiosum were variable (range 15.4-100%). Significant clearance of warts with maintenance of clearance was demonstrated with topical cantharidin alone. Topical cantharidin in combination with podophyllotoxin and salicylic acid demonstrated efficacy for plantar warts (pediatric and adult; clearance rate range 81-100%; four studies had 100% clearance), with the majority clearing after a single treatment. Satisfaction with cantharidin therapy was high, especially in molluscum contagiosum. Pain (7-85.7%), blistering (10-100%), and hyper-/hypopigmentation (1.8-53.3%) were the most commonly occurring adverse effects with cantharidin treatment.

CONCLUSION

Topical cantharidin demonstrated clearance of warts, particularly in combination with podophyllotixin and salicylic acid, and modest benefit for pediatric molluscum contagiosum with good tolerability and safety.

Innate Antiviral Immunity in the Skin

Barrier sites such as the skin play a critical role in immune defense. They must maintain homeostasis with commensals and rapidly detect and limit pathogen invasion. This is accomplished in part through the production of endogenous antimicrobial peptides and proteins, which can be either constitutive or inducible. Here, we focus particularly on the control of innate antiviral proteins and present the basic aspects of their regulation in the skin by interferons (IFNs), IFN-independent immunity, and environmental factors. We also discuss the activity and (dys-)function of antiviral proteins in the context of skin-tropic viruses and highlight the relevance of the innate antiviral pathway as a potential therapeutic avenue for vulnerable patient populations and skin diseases with high risk for virus infections.

Potential of small-molecule fungal metabolites in antiviral chemotherapy

Various viral diseases, such as acquired immunodeficiency syndrome, influenza, and hepatitis, have emerged as leading causes of human death worldwide. Scientific endeavor since invention of DNA-dependent RNA polymerase of pox virus in 1967 resulted in better understanding of virus replication and development of various novel therapeutic strategies. Despite considerable advancement in every facet of drug discovery process, development of commercially viable, safe, and effective drugs for these viruses still remains a big challenge. Decades of intense research yielded a handful of natural and synthetic therapeutic options. But emergence of new viruses and drug-resistant viral strains had made new drug development process a never-ending battle. Small-molecule fungal metabolites due to their vast diversity, stereochemical complexity, and preapproved biocompatibility always remain an attractive source for new drug discovery. Though, exploration of therapeutic importance of fungal metabolites has started early with discovery of penicillin, recent prediction asserted that only a small percentage (5-10%) of fungal species have been identified and much less have been scientifically investigated. Therefore, exploration of new fungal metabolites, their bioassay, and subsequent mechanistic study bears huge importance in new drug discovery endeavors. Though no fungal metabolites so far approved for antiviral treatment, many of these exhibited high potential against various viral diseases. This review comprehensively discussed about antiviral activities of fungal metabolites of diverse origin against some important viral diseases. This also highlighted the mechanistic details of inhibition of viral replication along with structure-activity relationship of some common and important classes of fungal metabolites.

Molluscum Contagiosum of the Gluteal Cleft: Observations and Implications for Management in Five Children

Molluscum contagiosum (MC) is a common, self-limited skin infection caused by a double-stranded DNA virus of the family Poxviridae. Although the morphology of the disease is well described, MC presenting at unusual sites can exhibit atypical morphology, resulting in misdiagnosis. This observational, retrospective case series discusses the novel morphology of MC presenting in the intergluteal cleft of five children seen in the outpatient dermatology clinic of an academic medical center. We present this case series to highlight this novel presentation of MC in children and to emphasize a conservative approach to management given the sensitive location and the self-limited nature of the infection.

Interventions for cutaneous molluscum contagiosum

BACKGROUND

Molluscum contagiosum is a common skin infection that is caused by a pox virus and occurs mainly in children. The infection usually resolves within months in people without immune deficiency, but treatment may be preferred for social and cosmetic reasons or to avoid spreading the infection. A clear evidence base supporting the various treatments is lacking.This is an update of a Cochrane Review first published in 2006, and updated previously in 2009.

OBJECTIVES

To assess the effects of specific treatments and management strategies, including waiting for natural resolution, for cutaneous, non-genital molluscum contagiosum in people without immune deficiency.

SEARCH METHODS

We updated our searches of the following databases to July 2016: the Cochrane Skin Group Specialised Register, CENTRAL, MEDLINE, Embase, and LILACS. We searched six trial registers and checked the reference lists of included studies and review articles for further references to relevant randomised controlled trials. We contacted pharmaceutical companies and experts in the field to identify further relevant randomised controlled trials.

SELECTION CRITERIA

Randomised controlled trials of any treatment of molluscum contagiosum in people without immune deficiency. We excluded trials on sexually transmitted molluscum contagiosum and in people with immune deficiency (including those with HIV infection).

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, assessed methodological quality, and extracted data from selected studies. We obtained missing data from study authors where possible.

MAIN RESULTS

We found 11 new studies for this update, resulting in 22 included studies with a total of 1650 participants. The studies examined the effects of topical (20 studies) and systemic interventions (2 studies).Among the new included studies were the full trial reports of three large unpublished studies, brought to our attention by an expert in the field. They all provided moderate-quality evidence for a lack of effect of 5% imiquimod compared to vehicle (placebo) on short-term clinical cure (4 studies, 850 participants, 12 weeks after start of treatment, risk ratio (RR) 1.33, 95% confidence interval (CI) 0.92 to 1.93), medium-term clinical cure (2 studies, 702 participants, 18 weeks after start of treatment, RR 0.88, 95% CI 0.67 to 1.14), and long-term clinical cure (2 studies, 702 participants, 28 weeks after start of treatment, RR 0.97, 95% CI 0.79 to 1.17). We found similar but more certain results for short-term improvement (4 studies, 850 participants, 12 weeks after start of treatment, RR 1.14, 95% CI 0.89 to 1.47; high-quality evidence). For the outcome 'any adverse effect', we found high-quality evidence for little or no difference between topical 5% imiquimod and vehicle (3 studies, 827 participants, RR 0.97, 95% CI 0.88 to 1.07), but application site reactions were more frequent in the groups treated with imiquimod (moderate-quality evidence): any application site reaction (3 studies, 827 participants, RR 1.41, 95% CI 1.13 to 1.77, the number needed to treat for an additional harmful outcome (NNTH) was 11); severe application site reaction (3 studies, 827 participants, RR 4.33, 95% CI 1.16 to 16.19, NNTH over 40).For the following 11 comparisons, there was limited evidence to show which treatment was superior in achieving short-term clinical cure (low-quality evidence): 5% imiquimod less effective than cryospray (1 study, 74 participants, RR 0.60, 95% CI 0.46 to 0.78) and 10% potassium hydroxide (2 studies, 67 participants, RR 0.65, 95% CI 0.46 to 0.93); 10% Australian lemon myrtle oil more effective than olive oil (1 study, 31 participants, RR 17.88, 95% CI 1.13 to 282.72); 10% benzoyl peroxide cream more effective than 0.05% tretinoin (1 study, 30 participants, RR 2.20, 95% CI 1.01 to 4.79); 5% sodium nitrite co-applied with 5% salicylic acid more effective than 5% salicylic acid alone (1 study, 30 participants, RR 3.50, 95% CI 1.23 to 9.92); and iodine plus tea tree oil more effective than tea tree oil (1 study, 37 participants, RR 0.20, 95% CI 0.07 to 0.57) or iodine alone (1 study, 37 participants, RR 0.07, 95% CI 0.01 to 0.50). Although there is some uncertainty, 10% potassium hydroxide appears to be more effective than saline (1 study, 20 participants, RR 3.50, 95% CI 0.95 to 12.90); homeopathic calcarea carbonica appears to be more effective than placebo (1 study, 20 participants, RR 5.57, 95% CI 0.93 to 33.54); 2.5% appears to be less effective than 5% solution of potassium hydroxide (1 study, 25 participants, RR 0.35, 95% CI 0.12 to 1.01); and 10% povidone iodine solution plus 50% salicylic acid plaster appears to be more effective than salicylic acid plaster alone (1 study, 30 participants, RR 1.43, 95% CI 0.95 to 2.16).We found no statistically significant differences for other comparisons (most of which addressed two different topical treatments). We found no randomised controlled trial evidence for expressing lesions or topical hydrogen peroxide.Study limitations included no blinding, many dropouts, and no intention-to-treat analysis. Except for the severe application site reactions of imiquimod, none of the evaluated treatments described above were associated with serious adverse effects (low-quality evidence). Among the most common adverse events were pain during application, erythema, and itching. Included studies of the following comparisons did not report adverse effects: calcarea carbonica versus placebo, 10% povidone iodine plus 50% salicylic acid plaster versus salicylic acid plaster, and 10% benzoyl peroxide versus 0.05% tretinoin.We were unable to judge the risk of bias in most studies due to insufficient information, especially regarding concealment of allocation and possible selective reporting. We considered five studies to be at low risk of bias.

AUTHORS' CONCLUSIONS

No single intervention has been shown to be convincingly effective in the treatment of molluscum contagiosum. We found moderate-quality evidence that topical 5% imiquimod was no more effective than vehicle in terms of clinical cure, but led to more application site reactions, and high-quality evidence that there was no difference between the treatments in terms of short-term improvement. However, high-quality evidence showed a similar number of general side effects in both groups. As the evidence found did not favour any one treatment, the natural resolution of molluscum contagiosum remains a strong method for dealing with the condition.

Marine and Other Aquatic Dermatoses

Occupational and recreational aquatic activity predisposes our population to a wide variety of dermatoses. Sunburn, urticaria, jellyfish stings, and contact dermatitis to rubber equipment are common allergies that are encountered in the aquatic environment. Among the infections, tinea versicolor, intertrigo, and verruca vulgaris are widespread. Swimmer's itch may occur due to skin penetration by schistosome cercariae, while free-floating nematocysts of marine coelenterates may precipitate seabather's eruption. "Suit squeeze" due to cutaneous barotrauma and lymphoedematous peau d'orange due to decompression are rare, described entities. This review serves as a ready reckoner for Indian dermatologists and medical practitioners to identify and manage these conditions.

Immune evasion strategies of molluscum contagiosum virus

Molluscum contagiosum virus (MCV) is the causative agent of molluscum contagiosum (MC), the third most common viral skin infection in children, and one of the five most prevalent skin diseases worldwide. No FDA-approved treatments, vaccines, or commercially available rapid diagnostics for MCV are available. This review discusses several aspects of this medically important virus including: physical properties of MCV, MCV pathogenesis, MCV replication, and immune responses to MCV infection. Sequencing of the MCV genome revealed novel immune evasion molecules which are highlighted here. Special attention is given to the MCV MC159 and MC160 proteins. These proteins are FLIPs with homologs in gamma herpesviruses and in the cell. They are of great interest because each protein regulates apoptosis, NF-κB, and IRF3. However, the mechanism that each protein uses to impart its effects is different. It is important to elucidate how MCV inhibits immune responses; this knowledge contributes to our understanding of viral pathogenesis and also provides new insights into how the immune system neutralizes virus infections.

Time to resolution and effect on quality of life of molluscum contagiosum in children in the UK: a prospective community cohort study

BACKGROUND

Molluscum contagiosum is one of the 50 most prevalent diseases worldwide, but scarce epidemiological data exist for childhood molluscum contagiosum. We aimed to describe the time to resolution, transmission to household child contacts, and effect on quality of life of molluscum contagiosum in children in the UK.

METHODS

Between Jan 1, and Oct 31, 2013, we recruited 306 children with molluscum contagiosum aged between 4 and 15 years in the UK either by referral by general practitioner or self-referral (with diagnosis made by parents by use of the validated Molluscum Contagiosum Diagnostic Tool for Parents [MCDTP]). All participants were asked to complete a questionnaire at recruitment about participant characteristics, transmission, and quality of life. We measured quality of life with the Children's Dermatology Life Quality Index (CDLQI). Participants were prospectively followed up every month to check on their recovery from molluscum contagiosum and transmission to other children in the same household, until the child's lesions were no longer visible.

FINDINGS

The mean time to resolution was 13·3 months (SD 8·2). 80 (30%) of 269 cases had not resolved by 18 months; 36 (13%) had not resolved by 24 months. We recorded transmission to other children in the household in 102 (41%) of 250 cases. Molluscum contagiosum had a small effect on quality of life for most participants, although 33 (11%) of 301 participants had a very severe effect on quality of life (CDLQI score >13). A greater number of lesions was associated with a greater effect on quality of life (H=55·8, p<0·0001).

INTERPRETATION

One in ten children with molluscum contagiosum is likely to have a substantial effect on their quality of life and therefore treatment should be considered for some children, especially those with many lesions or who have been identified as having a severe effect on quality of life. Patients with molluscum contagiosum and their parents need to be given accurate information about the expected natural history of the disorder. Our data provide the most reliable estimates of the expected time to resolution so far and can be used to help set realistic expectations.

FUNDING

Wales School of Primary Care Research (WSPCR) and Cardiff University.

A novel target and approach for identifying antivirals against molluscum contagiosum virus

The dermatological disease molluscum contagiosum (MC) presents as lesions restricted solely to the skin. The poxvirus molluscum contagiosum virus (MCV) is responsible for this skin disease that is easily transmitted through casual contact among all populations, with greater frequency in children and immunosuppressed individuals. In addition, sexual transmission of MCV in adolescents and adults is a health concern. Although the skin lesions ultimately resolve in immunocompetent individuals, they can persist for extended periods, be painful, and result in scarring. Treatment is problematic, and there is no drug that specifically targets MCV. The inability of MCV to propagate in cell culture has impeded drug development. To overcome these barriers, we integrated three new developments. First, we identified a new MCV drug target (mD4) that is essential for processive DNA synthesis in vitro. Second, we discovered a small chemical compound that binds to mD4 and prevents DNA synthesis in vitro. Third, and most significant, we engineered a hybrid vaccinia virus (mD4-VV) in which the natural vaccinia D4 (vD4) gene is replaced by the mD4 target gene. This hybrid virus is dependent on mD4 for viral growth in culture and is inhibited by the small compound. This target system provides, for the first time, a platform and approach for the discovery and evaluation of new therapeutics that can be used to treat MC.

Epidemiology of molluscum contagiosum in children: a systematic review

BACKGROUND

Molluscum contagiosum (MC) is a common skin condition that primarily affects children, a common reason for presenting in primary care and is commonly seen in children presenting with other conditions in primary and secondary care. It is usually asymptomatic but can present with pain, pruritus, erythema and bacterial superinfection. Aim. To synthesize the current epidemiology of MC. Design and setting. A systematic literature review of bibliographical databases on the prevalence, incidence, risk factors, age distribution and association with other conditions for MC in children.

RESULTS

Data on the epidemiology of MC is largely of poor quality. The largest incidence is in children aged between 0 and 14 years, where the incidence rate ranged from 12 to 14 episodes per 1000 children per year. Incidence rates in the UK were highest in those aged 1-4 years. Meta-analysis suggests a point prevalence in children aged 0-16 years of between 5.1% and 11.5%. There is evidence for an association between swimming and having MC and MC is more common in those with eczema; however, there is little evidence for other risk factors.

CONCLUSIONS

MC is a common condition, with the greatest incidence being in those aged 1-4 years. Swimming and eczema are associated with the presence of MC, but the causal relationships are unclear. There is a lack of data regarding the natural history of MC and published data are insufficient to determine temporal or geographic patterns in incidence, risk factors, duration of symptoms or transmission between family members.

Seroprevalence of Molluscum contagiosum virus in German and UK populations

Molluscum contagiosum virus (MCV) is a significant but underreported skin pathogen for children and adults. Seroprevalence studies can help establish burden of disease. Enzyme linked immunosorbent assay (ELISA) based studies have been published for Australian and Japanese populations and the results indicate seroprevalences between 6 and 22 percent in healthy individuals, respectively. To investigate seroprevalence in Europe, we have developed a recombinant ELISA using a truncated MCV virion surface protein MC084 (V123-R230) expressed in E. coli. The ELISA was found to be sensitive and specific, with low inter- and intra-assay variability. Sera from 289 German adults and children aged 0-40 years (median age 21 years) were analysed for antibodies against MC084 by direct binding ELISA. The overall seropositivity rate was found to be 14.8%. The seropositivity rate was low in children below the age of one (4.5%), peaked in children aged 2-10 years (25%), and fell again in older populations (11-40 years; 12.5%). Ten out of 33 healthy UK individuals (30.3%; median age 27 years) had detectable MC084 antibodies. MCV seroconversion was more common in dermatological and autoimmune disorders, than in immunocompromised patients or in patients with multiple sclerosis. Overall MCV seroprevalence is 2.1 fold higher in females than in males in a UK serum collection. German seroprevalences determined in the MC084 ELISA (14.8%) are at least three times higher than incidence of MC in a comparable Swiss population (4.9%). While results are not strictly comparable, this is lower than Australian seroprevalence in a virion based ELISA (n = 357; 23%; 1999), but higher than the seroprevalence reported in a Japanese study using an N-terminal truncation of MC133 (n = 108, 6%; 2000. We report the first large scale serological survey of MC in Europe (n = 393) and the first MCV ELISA based on viral antigen expressed in E. coli.

Molluscum contagiosum virus infection

Molluscum contagiosum virus is an important human skin pathogen: it can cause disfigurement and suffering in children, in adults it is less common and often sexually transmitted. Extensive and persistent skin infection with the virus can indicate underlying immunodeficiency. Traditional ablative therapies have not been compared directly with newer immune-modulating and specific antiviral therapies. Advances in research raise the prospect of new approaches to treatment informed by the biology of the virus; in human skin, the infection is localised in the epidermal layers, where it induces a typical, complex hyperproliferative lesion with an abundance of virus particles but a conspicuous absence of immune effectors. Functional studies of the viral genome have revealed effects on cellular pathways involved in the cell cycle, innate immunity, inflammation, and cell death. Extensive lesions caused by molluscum contagiosum can occur in patients with DOCK8 deficiency-a genetic disorder affecting migration of dendritic and specialised T cells in skin. Sudden disappearance of lesions is the consequence of a vigorous immune response in healthy people. Further study of the unique features of infection with molluscum contagiosum virus could give fundamental insight into the nature of skin immunity.

Molluscum contagiosum virus: persistence pays off

The molluscum contagiosum (MC) virus (MCV) is a dermatotropic poxvirus, and the causative agent of MC. Unlike smallpox and human monkeypox diseases, MC is nonlethal, common and worldwide. Additionally, little inflammation is associated with MC papules, and MC can persist for months to years. Such a prolonged infection implies that MCV successfully manipulates the host environment. This review highlights recent findings that reveal how MCV infections manipulate localized host immune responses and which immune response are key for the eventual resolution of MC. Also highlighted here are the MCV proteins that inhibit apoptosis, inflammation and immune cell recruitment or that induce cellular proliferation, with discussion as to how these proteins dampen localized antiviral immune responses. Lastly, this review discusses how the immune evasion tactics of MCV have led to insights about specific functions of the human innate and adaptive immune responses.

Aquatic sports dermatoses: part 1. In the water: freshwater dermatoses

The first of this three-part series on water-related dermatoses involving the athlete will include sports occurring with the majority of time spent in the water. These sports include swimming, diving, scuba, snorkeling and water polo. Numerous authors have described dermatologic conditions commonly seen in swimmers. This series provides an updated and comprehensive review of these water dermatoses. In order to organize the vast number of skin conditions related to water exposure, we divided the skin conditions into groupings of infectious and organism-related dermatoses, irritant and allergic dermatoses and miscellaneous dermatoses. The vast majority of skin conditions involving the water athlete result from chemicals and microbes inhabiting each environment. When considering the effects of swimming on one's skin, it is also useful to differentiate between exposure to freshwater (lakes, ponds and swimming pools) and exposure to saltwater. This review will serve as a guide for dermatologists, sports medicine physicians and other medical practitioners in recognition and treatment of these conditions.

National athletic trainers' association position statement: skin diseases

OBJECTIVE

To present recommendations for the prevention, education, and management of skin infections in athletes.

BACKGROUND

Trauma, environmental factors, and infectious agents act together to continually attack the integrity of the skin. Close quarters combined with general poor hygiene practices make athletes particularly vulnerable to contracting skin diseases. An understanding of basic prophylactic measures, clinical features, and swift management of common skin diseases is essential for certified athletic trainers to aid in preventing the spread of infectious agents.

RECOMMENDATIONS

These guidelines are intended to provide relevant information on skin infections and to give specific recommendations for certified athletic trainers and others participating in athletic health care.

Padrões dermatoscópicos do molusco contagioso: estudo de 211 lesões confirmadas por exame histopatológico

FUNDAMENTOS: Embora de fácil diagnóstico, o molusco contagioso pode apresentar-se como lesões inflamadas, únicas ou pequenas de difícil diagnóstico. OBJETIVO: Descrever características dermatoscópicas do molusco contagioso e comparar achados do exame clínico e dermatoscópico. MÉTODOS: Avaliou-se clínica e dermatoscopicamente lesões confirmadas pela histopatologia em 57 pacientes. RESULTADOS: Nos exames clínico e dermatoscópico de 211 lesões, foram visualizados orifícios em 50,24% e 96,68% das lesões e vasos em 6,16% e 89,10% delas, respectivamente. Os padrões vasculares encontrados em 188 lesões que apresentaram vasos à dermatoscopia foram coroa (72,34%), radial (54,25%) e puntiforme (20,21%). Metade das 188 lesões apresentou padrão vascular combinado, sendo o padrão em flor (novo padrão vascular) responsável por 19,68%. Foram identificados mais orifícios e vasos no exame dermatoscópico que no clínico, inclusive naquelas com inflamação, eczema perilesional e de tamanho pequeno. Vasos puntiformes relacionaram-se com inflamação, escoriação e eczema perilesional. CONCLUSÕES: A dermatoscopia das lesões de molusco mostrou-se superior ao exame dermatológico mesmo quando seu diagnóstico clínico torna-se difícil. A presença de orifícios, vasos e padrões vasculares específicos auxilia no seu diagnóstico e na diferenciação de outras lesões de pele.

Interventions for cutaneous molluscum contagiosum

BACKGROUND

Molluscum contagiosum is a common skin infection, caused by a pox virus. The infection will usually resolve within months in people with a normal immune system. Many treatments have been used for molluscum contagiosum but a clear evidence base supporting them is lacking.This is an updated version of the original Cochrane Review published in Issue 2, 2006.

OBJECTIVES

To assess the effects of management strategies (including waiting for natural resolution) for cutaneous, non-genital molluscum contagiosum in otherwise healthy people.

SEARCH STRATEGY

In June 2009 we updated our searches of the Cochrane Skin Group Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library (Issue 2, 2009), MEDLINE, EMBASE, and LILACS. We also searched ongoing trials registers, reference lists, and contacted pharmaceutical companies and experts in the field.

SELECTION CRITERIA

We investigated randomised controlled trials (RCTs) for the treatment of molluscum contagiosum. We excluded trials on sexually transmitted molluscum contagiosum and in people with lowered immunity (including those with HIV infection).

DATA COLLECTION AND ANALYSIS

Two authors independently selected studies, assessed methodological quality, and extracted data from selected studies.

MAIN RESULTS

Eleven studies, with a total number of 495 participants, examined the effects of topical (9 studies), systemic, and homoeopathic interventions (1 study each). Limited evidence was found for the efficacy of sodium nitrite co-applied with salicylic acid compared to salicylic acid alone (risk ratio (RR) 3.50, 95% confidence interval (CI) 1.23 to 9.92); for Australian lemon myrtle oil compared to its vehicle, olive oil (RR 17.88, 95% CI 1.13 to 282.72); and for benzoyl peroxide cream compared to tretinoin (RR 2.20, 95% CI 1.01 to 4.79). No statistically significant differences were found for 10 other comparisons, most of which addressed 2 topical treatments.Study limitations included no blinding (four studies), many dropouts (three studies), and no intention-to-treat analysis; small study sizes may have led to important differences being missed. None of the evaluated treatment options were associated with serious adverse effects.

AUTHORS' CONCLUSIONS

No single intervention has been shown to be convincingly effective in the treatment of molluscum contagiosum. The update identified six new studies, most of them reporting on interventions not included in the original version. However, the conclusions of the review did not change.

Poxvirus host range genes

As a family of viruses, poxviruses collectively exhibit a broad host range and most of the individual members are capable of replicating in a wide array of cell types from various host species, at least in vitro. At the cellular level, poxvirus tropism is dependent not upon specific cell surface receptors, but rather upon: (1) the ability of the cell to provide intracellular complementing factors needed for productive virus replication, and (2) the ability of the specific virus to successfully manipulate intracellular signaling networks that regulate cellular antiviral processes downstream of virus entry. The large genomic coding capacity of poxviruses enables the virus to express a unique collection of viral proteins that function as host range factors, which specifically target and manipulate host signaling pathways to establish optimal cellular conditions for viral replication. Functionally, the known host range factors from poxviruses have been associated with manipulation of a diverse array of cellular targets, which includes cellular kinases and phosphatases, apoptosis, and various antiviral pathways. To date, only a small number of poxvirus host range genes have been identified and studied, and only a handful of these have been functionally characterized. For this reason, poxvirus host range factors represent a potential gold mine for the discovery of novel pathogen-host protein interactions. This review summarizes our current understanding of the mechanisms by which the known poxvirus host range genes, and their encoded factors, expand tropism through the manipulation of host cell intracellular signaling pathways.

Identification and genotyping of molluscum contagiosum virus from genital swab samples by real-time PCR and Pyrosequencing

BACKGROUND

Laboratory diagnosis of molluscum contagiosum virus (MCV) is important as lesions can be confused with those caused by Cryptococcus neoformans, herpes simplex virus, human papillomavirus, and varicella-zoster virus.

OBJECTIVES

To develop a rapid method for identifying patients infected with MCV via swab sampling.

STUDY DESIGN

Two dual-labeled probe real-time PCR assays, one homologous to the p43K gene and one to the MC080R gene, were designed. The p43K PCR was designed to be used in conjunction with Pyrosequencing for confirmation of PCR products and discrimination between MCV1 and MCV2.

RESULTS

Both PCR assays were optimized with respect to reaction components, thermocycling parameters, and primer and probe concentrations. The specificities of both PCR assays were confirmed by non-amplification of 38 known human pathogens. Sensitivity assays demonstrated detection of as few as 10 copies per reaction. Testing 703 swabs, concordance between the two real-time PCR assays was 99.9%. Under the developed conditions, Pyrosequencing of the p43K PCR product was capable of providing enough nucleotide sequence to definitively differentiate MCV1 and MCV2.

CONCLUSIONS

These real-time PCR assays can be used for the rapid, sensitive, and specific detection of MCV and, when combined with Pyrosequencing, can further discriminate between MCV1 and MCV2.

Purple penile papules

Molluscum contagiosum may present in a variety of clinical and pathologic guises. We present the clinicopathologic features of an unusual case that initially was misinterpreted as bowenoid papulosis. The relevant histologic attributes of this case include the presence of a violaceous hyperplastic squamous epithelium adjacent to the infected keratinocytes. The presence of this violaceous cytoplasmic staining should prompt a search for molluscum in the appropriate clinical context.

Tropism of Tanapox virus infection in primary human cells

Tanapox virus (TPV) belongs to the genus Yatapoxvirus and causes a relatively benign zoonotic disease in man, with symptoms that resemble a mild version of human monkeypox. In order to investigate the underlying mechanisms of TPV pathogenesis, the tropism and replication characteristics of TPV were examined in a variety of primary human cells. A GFP expressing TPV (TPV-GFP) was constructed and used to infect primary human dermal fibroblasts (pHDFs) and peripheral blood mononuclear cells (PBMCs), both of which are believed to be major in vivo targets of poxvirus infection. pHDFs fully supported productive replication and cell-cell spread of TPV-GFP. However, induction of cell cycle arrest in pHDFs by contact mediated inhibition or rapamycin treatment eliminated the ability of TPV to fully stimulate cell cycle progression and dramatically reduced viral replication. TPV-GFP-infected human PBMCs were screened for permissiveness by FACS analysis. CD14+ cells (monocytes) were the primary cellular target for TPV infection. A small proportion of CD3+ cells (T cells) were positive for GFP expression, yet TPV was not able to replicate and spread in cultured peripheral blood lymphocytes, regardless of their state of activation. Primary human monocytes, however, demonstrated robust TPV replication, yet these cells no longer supported replication of TPV once they differentiated into macrophages. This unique ex vivo tropism of TPV gives key insights into the basis for the self-limiting pathogenicity of TPV in man.

Variola virus IL-18 binding protein interacts with three human IL-18 residues that are part of a binding site for human IL-18 receptor alpha subunit

Interleukin-18 (IL-18) plays an important role in host defense against microbial pathogens. Many poxviruses encode homologous IL-18 binding proteins (IL-18BP) that neutralize IL-18 activity. Here, we examined whether IL-18BP neutralizes IL-18 activity by binding to the same region of IL-18 where IL-18 receptor (IL-18R) binds. We introduced alanine substitutions to known receptor binding sites of human IL-18 and found that only the substitution of Leu5 reduced the binding affinity of IL-18 with IL-18BP of variola virus (varvIL-18BP) by more than 4-fold. The substitutions of Lys53 and Ser55, which were not previously known to be part of the receptor binding site but that are spatially adjacent to Leu5, reduced the binding affinity to varvIL-18BP by approximately 100- and 7-fold, respectively. These two substitutions also reduced the binding affinity with human IL-18R alpha subunit (hIL-18Ralpha) by 4- and 2-fold, respectively. Altogether, our data show that varvIL-18BP prevents IL-18 from binding to IL-18R by interacting with three residues that are part of the binding site for hIL-18Ralpha.

Viral infections affecting the skin in organ transplant recipients: epidemiology and current management strategies

Viral skin infections are common findings in organ transplant recipients. The most important etiological agents are the group of human herpesviruses (HHV), human papillomaviruses (HPV), and molluscum contagiosum virus. HHV that are important in this group of patients are herpes simplex virus (HSV) types 1 and 2, varicella-zoster virus (VZV), cytomegalovirus (CMV), Epstein-Barr virus (EBV), HHV-6 and -7, and HHV-8, which causes Kaposi sarcoma (KS). HSV infections are characterized by their ability to establish latency and then reactivate at a later date. The most common manifestations of HSV infection in organ transplant recipients are mucocutaneous lesions of the oropharynx or genital regions. Treatment is usually with acyclovir, valaciclovir, or famciclovir. Acyclovir resistance may arise although the majority of acyclovir-resistant strains have been isolated from AIDS patients and not organ transplant recipients. In such cases, alternatives such as foscarnet, cidofovir, or trifluridine may have to be considered. VZV causes chickenpox as well as herpes zoster. In organ transplant recipients, recurrent herpes zoster can occur. Acute chickenpox in organ transplant patients should be treated with intravenous acyclovir. CMV infection occurs in 20-60% of all transplant recipients. Cutaneous manifestations, which include nonspecific macular rashes, ulcers, purpuric eruptions, and vesiculobullous lesions, are seen in 10-20% of patients with systemic infection and signify a poor prognosis. The present gold standard for treatment is ganciclovir, but newer drugs such as valganciclovir appear promising. EBV is responsible for some cases of post-transplant lymphoproliferative disorder, which represents the greatest risk of serious EBV disease in transplant recipients. HHV-6 and HHV-7 are two relatively newly discovered viruses and, at present, the body of information concerning these two agents is still fairly limited. KS is caused by HHV-8, which is the most recently discovered lymphotrophic HHV. Iatrogenic KS is seen in solid-organ transplant recipients, with a prevalence of 0.5-5% depending on the patient's country of origin. HPV is ubiquitous, and organ transplant recipients may never totally clear HPV infections, which are the most frequently recurring infections in renal transplant recipients. HPV infection in transplant recipients is important because of its link to the development of certain skin cancers, in particular, squamous cell carcinoma. Regular surveillance, sun avoidance, and patient education are important aspects of the management strategy.

Double-blind, randomized, placebo-controlled trial of the use of topical 10% potassium hydroxide solution in the treatment of molluscum contagiosum

Molluscum contagiosum is a common viral infection of the skin that frequently affects children. Lesions take between 6 and 18 months to resolve spontaneously and are a source of great embarrassment to both caretakers and children, often affecting attendance at school and limiting social activity. Treatment options to date have been poorly tolerated by children but recent studies have suggested that potassium hydroxide may be beneficial. This double-blind, randomized, placebo-controlled study compared 10% potassium hydroxide with placebo (normal saline). Twenty patients, aged 2 to 12 years, were recruited. Parents applied a solution twice daily to lesional skin until signs of inflammation appeared. Children were examined by the same observer on days 0, 15, 30, 60, and 90. Seventy percent of children receiving topical potassium hydroxide cleared, compared with 20% in the placebo group. Further dosing studies are required to identify whether weaker concentrations of potassium hydroxide are as efficacious, with less irritancy.

Interventions for cutaneous molluscum contagiosum

BACKGROUND

Molluscum contagiosum is a common skin infection, caused by a virus, which will usually resolve within months in people with a normal immune system. Many treatments have been promoted for molluscum contagiosum but a clear evidence base supporting them is lacking.

OBJECTIVES

To assess the effects of management strategies (including waiting for natural resolution) for cutaneous, non-genital molluscum contagiosum in healthy people.

SEARCH STRATEGY

We searched the Skin Group Specialised Register (March 2004), the Cochrane Central Register of Controlled Trials (2004, Issue 2), MEDLINE (from 1966 to March 2004), EMBASE (from 1980 to March 2004) and LILACS (from 1982 to March 2004) databases. We also searched reference lists and contacted pharmaceutical companies and experts in the field.

SELECTION CRITERIA

Randomised controlled trials for treatment of molluscum contagiosum were investigated. Trials on sexually transmitted molluscum contagiosum and in people with lowered immunity (including those with HIV infection) were excluded.

DATA COLLECTION AND ANALYSIS

Study selection and assessment of methodological quality were carried out by two independent authors. As similar comparisons between two interventions were not made in more than one study, statistical pooling was not performed.

MAIN RESULTS

Five studies, with a total number of 137 participants, examined the effects of topical (three studies), systemic and homoeopathic interventions (one study each). Limited evidence was found for sodium nitrite co-applied with salicylic acid compared to salicylic acid alone (risk ratio (RR) 3.50, 95% confidence interval (CI) 1.23 to 9.92). No statistically significant differences were found for topical povidone iodine plus salicylic acid compared to povidone iodine alone (RR of cure 1.67, 95% CI 0.81 to 3.41) or compared to salicylic acid alone. Also no statistically significant differences were found for potassium hydroxide compared to placebo; systemic treatment with cimetidine versus placebo or systemic treatment with calcarea carbonica, a homoeopathic drug, versus placebo (RR 5.57, 95% CI 0.93 to 33.54). Study limitations included no blinding (two studies), many dropouts (three studies) and no intention-to-treat analysis (two studies); small study sizes may have led to important differences being missed. None of the evaluated treatment options were associated with serious adverse effects.

AUTHORS' CONCLUSIONS

No single intervention has been shown to be convincingly effective in treating molluscum contagiosum.

Detection of Molluscum contagiosum Virus (MCV) Subtype I as a Single Dominant Virus Subtype in Molluscum Lesions from a Turkish Population

BACKGROUND

Molluscum contagiosum has a worldwide occurrence and its primary mode of transmission is via direct human contact including sexual means. The aim of the study was to implement a polymerase chain reaction-based assay for detection and subtyping of Molluscum contagiosum virus (MCV) in skin lesions diagnosed with molluscum contagiosum in a large regional teaching hospital in Turkey.

METHODS

For this purpose, a total of 61 patients were included in the study. Randomly selected single lesion from each patient was used to extract DNA material and a specific PCR reaction amplifying 393-bp- and 575-bp-long regions from MCV genome was used in the detection. Subtyping was carried out by digestion of the amplified 575-bp product with restriction endonuclease enzyme BamHI. Both amplified and restriction enzyme digested products visualized on agarose gel electrophoresis.

RESULTS

All 61 molluscum cases (100%) included in the study contained MCV genetic material as demonstrated by the presence of 393- and 575-bp-long PCR amplified products. Restriction enzyme BamHI digestion of the 575-bp-long amplicon indicated that the infecting subtype in all the cases (100%) was MCV subtype I.

CONCLUSIONS

Results of this study demonstrate that subtype I is the only infecting strain dominant in our region. Because the only consecutive molluscum patients admitted to our hospital were included in the study, our data do not rule out the possibility that other genotypes might be present in the Turkish population. However, it is not unreasonable to conclude that similar trends exist in the rest of the country. Results also show that a molecular-based diagnostic assay would be feasible in cases where diagnosis was deemed necessary.