An overview of poxviruses

Bullous dermatoses in childhood: part I

A classification of bullous dermatoses in childhood is presented, according to the histologic location of the bulla and the heritability of the disease, combined with the most recent laboratory examinations used in dermatologic practice. For a better understanding of the proposed classification, the authors also present a review of this group of diseases, which vary greatly within the group. In this first part of the classification and review, the group of bullous dermatoses with nonhereditary characteristics and intraepidermal cleavage is described.

Virus-encoded G-protein-coupled receptors: constitutively active (dys)regulators of cell function and their potential as drug target

G-protein-coupled receptors encoded by herpesviruses such as EBV, HCMV and KSHV are very interesting illustrations of the (patho)physiological importance of constitutive GPCR activity. These viral proteins are expressed on the cell surface of infected cells and often constitutively activate a variety of G-proteins. For some virus-encoded GPCRs, the constitutive activity has been shown to occur in vivo, i.e., in infected cells. In this paper, we will review the occurrence of virus-encoded GPCRs and describe their known signaling properties. Moreover, we will also review the efforts, directed towards the discovery of small molecule antagonist, that so far have been mainly focused on the HCMV-encoded GPCR US28. This virus-encoded receptor might be involved in cardiovascular diseases and cancer and seems an interesting target for drug intervention.

Specimens from a vesicular lesion caused by molluscum contagiosum virus produced a cytopathic effect in cell culture that mimicked that produced by herpes simplex virus

Infection with molluscum contagiosum virus, a poxvirus, normally has a typical clinical presentation; therefore, laboratory confirmation is infrequently sought and the virus is rarely isolated in culture. As reported herein, viral culture of specimens from atypical lesions may produce an abortive infection in limited cell lines and a cytopathic effect suggestive of herpes simplex virus.

Training Room Management of Medical Conditions: Sports Dermatology

Athletes' skin is subject to a distinct array of physical and environmental stressors. Trauma, the elements, and pathogenic organisms constantly challenge the skin's integrity. This article intends to arm the clinician with a fundamental knowledge of infections, mechanical injuries, and environmental insults common to the skin of athletes. Photographs corresponding to the described entities are included as figures. Because rapid return to play is the ultimate goal after injury or illness, there is a section dedicated to play restrictions as set forth by the National Collegiate Athletic Association. Although the evaluation and management of cutaneous disease is a challenging endeavor, a consistent and systematic approach to this most accessible organ can result in early diagnosis, appropriate treatment, and ultimate performance.

Milkers’ Nodules Complicated by Erythema Multiforme and Graft‐versus‐Host Disease after Allogeneic Hematopoietic Stem Cell Transplantation for Multiple Myeloma

We describe a case of cow-transmitted parapoxvirus infection--also known as milkers' nodules--after a hematopoietic stem cell transplantation for multiple myeloma. The infection was complicated by erythema multiforme and acute exacerbation of graft-versus-host disease. Parapoxvirus was confirmed by electron microscopy. The natural history of milker's nodules in immunocompetent hosts is described and compared to that in our immunocompromised patient.

Molluscum contagiosum in Greek children: a case series

BACKGROUND

Epidemiological studies of molluscum contagiosum (MC) in children are limited.

PATIENTS AND METHOD

Between 1997 and 1999, 110 children with MC (60 boys, 50 girls, mean age: 4.8 years) were studied. Treatment consisted of removal of all MC lesions in a single session by sterilized tweezers.

RESULTS

In children aged < or = 2 years, the MC lesions were located mainly on the face, whereas in older children they were located on the trunk. Twenty children had atopic dermatitis (18.2% vs. 5% of Greek children aged 1-6 years; P < 0.001). Four children had numerous and recurrent MC lesions without any other systemic manifestations. In these children, humoral and cellular immunities were found to be normal. Seventy-seven children (70%) were cured after one treatment session, 22 children (20%) after a second session and 11 (10%) after > or = three sessions. No patients experienced secondary bacterial infection or scarring.

CONCLUSIONS

In contrast to cool climates where the age of peak incidence of MC in children is 10-12 years, in a warm country such as Greece, it is at the younger age of 4.8 years. In young children aged 2 years, the MC lesions are located mainly on the face, whereas in older children they are located on the trunk. Atopic dermatitis is a predisposing factor for MC. In cases where MC lesions are numerous and/or persist but there are no other signs of systemic infections, the possibility of immunodeficiency is minimal. Removal of MC lesions by tweezers is an efficient, simple and inexpensive method of treatment without sequelae.

Reactive oxygen signaling and MAPK activation distinguish Epstein-Barr Virus (EBV)-positive versus EBV-negative Burkitt's lymphoma

Burkitt's lymphoma (BL) is an aggressive B cell neoplasm, which is one of the most common neoplasms of childhood. It is highly widespread in East Africa, where it appears in endemic form associated with Epstein-Barr virus (EBV) infection, and around the world in a sporadic form in which EBV infection is much less common. In addition to being the first human neoplasm to be associated with EBV, BL is associated with a characteristic translocation, in which the Ig promoter is translocated to constitutively activate the c-myc oncogene. Although many BLs respond well to chemotherapy, a significant fraction fails to respond to therapy, leading to death. In this article, we demonstrate that EBV-positive BL expresses high levels of activated mitogen-activated protein kinase and reactive oxygen species (ROS), and that ROS directly regulate NF-kappaB activation. EBV-negative BLs exhibit activation of phosphoinositol 3-kinase, but do not have elevated levels of ROS. Elevated reactive oxygen may play a role in diverse forms of viral carcinogenesis in humans, including cancers caused by EBV, hepatitis B, C, and human T cell lymphotropic virus. Our findings imply that inhibition of ROS may be useful in the treatment of EBV-induced neoplasia.

Multiple giant molluscum contagiosum in a renal transplant recipient

Atypical presentations of molluscum contagiosum (MC) infection can be expected in renal transplant recipients, as a result of long-term immunosuppression. However, giant MC has rarely been reported in this population. We present a 28-year-old female renal transplant recipient receiving immunosuppressive therapy who developed multiple giant MC lesions on her axillary folds. The lesions were treated successfully with curettage and electrocauterization.

Emerging viral infections

"Emerging infections" have been defined as infections that have newly appeared, that have appeared previously but are expanding in incidence and geographic range, or that threaten to increase in the near future. This article focuses on nine emerging viral infectious agents. These viruses illustrate how such agents emerge: by encroaching on previously unvisited habitats (eg, hantaviruses), by air travel (eg, SARS), and by accidental importation (eg, monkeypox). Additionally, the example of SARS demonstrates not only how quickly emerging viral infections can spread but also how quickly they can be identified and contained with motivated cooperation.

Milker's nodule in a healthy young woman

Milker's nodules (pseudocowpox) are harmless skin lesions most commonly seen in persons whose occupation regularly brings them into close contact with cattle. They are caused by the paravaccinia virus, a member of the poxvirus family. Awareness of their clinical and histopathologic features is important, especially with today's heightened awareness of the threat of biologic warfare, to distinguish them from more worrisome entities such as tularemia and anthrax.

Activation of the D Prostanoid Receptor 1 Regulates Immune and Skin Allergic Responses

The mobilization of Langerhans cells (LCs) from epithelia to the draining lymph nodes is an essential process to initiate primary immune responses. We have recently shown that in mice, PGD2 is a potent inhibitor of epidermal LC emigration. In this study, we demonstrate that activation of the D prostanoid receptor 1 (DP1) impedes the TNF-alpha-induced migration of human LCs from skin explants and strongly inhibits the chemotactic responses of human LC precursors and of maturing LCs to CC chemokine ligands 20 and 19, respectively. Using a murine model of atopic dermatitis, a chronic Th2-type allergic inflammatory disease, we demonstrate that the potent DP1 agonist BW245C dramatically decreases the Ag-specific T cell activation in the skin draining lymph nodes and markedly prevents the skin lesions following repeated epicutaneous sensitization with OVA. Interestingly, analysis of the local response indicates that BW245C treatment strongly reduces the recruitment of inflammatory cells into the dermis and disrupts the Th1/Th2 balance, probably through the increased production of the immunoregulatory cytokine IL-10, in the skin of sensitized mice. Taken together, our results suggest a new function for DP1 in the regulation of the immune and inflammatory responses. We propose that DP1 activation by specific agonists may represent a strategy to control cutaneous inflammatory Th2-associated diseases.

Pediatric molluscum contagiosum: optimal treatment strategies

Pediatric molluscum contagiosum virus (MCV) is a common pox viridae infection that represents a common public health issue. The spread of the virus among children is rapid and easy. The virus produces a number of substances that block immune response formation in the infected host. Despite the benign and self-limited nature of the condition, one-third of children have symptoms from, or secondary reactions to the infection, including pruritus, erythema and, occasionally, inflammation and pain. Patients with pruritus autoinoculate the virus through scratching, thereby exacerbating their conditions. While adults cope well with unanesthetized curettage of lesions, children require less painful therapeutic options. The options for therapy are manifold. Therapy should begin with gentle skin care and antipruritics to prevent symptoms, and to prevent the spread of the disease. Therapies with good efficacy and low risk of pain for the patient include in-office usage of cantharidin and the use of local anesthetics, such as topical lidocaine (lignocaine) preparations in combination with the curettage of visible lesions. Alternatively, cryosurgery can be performed to eradicate lesions in-office. At-home therapeutics are often preferred by parents and children, and include imiquimod, retinoids, and alpha-hydroxy acids. Although a variety of such at-home therapies are available, none are as effective or as rapid acting as in-office therapy. Further research in large clinical trials is required to increase knowledge on prevention, optimal treatment, and long-term outcome with this disease.

Feline orthopoxvirus infection transmitted from cat to human

We report the case of a 56-year-old female patient who presented with an inflamed, ulcerated lesion on the left side of her neck after contact (scratch) with a cat living in the patient's house. Satellite lesions developed despite local treatment and parenteral clindamycin. Histopatholgic examination and the Tzanck test showed evidence of a viral infection. Subsequent transmission electron microscopy of scrap tissue and material from a fresh pustule exhibited multiple typical poxvirus particles, predominantly in remnants of scaled-off layers of degenerated keratinocytes, and virus particles in intermingled phagocytes, leading to the diagnosis of feline Orthopoxvirus (cowpox virus) infection. These results were verified by polymerase chain reaction and sequencing. Concern has been raised as to whether discontinuation of smallpox vaccine would cause an increase in Orthopoxvirus infection, but this has not yet shown to be the case.

Disseminated and disfiguring molluscum contagiosum in a child

We report widely disseminated and disfiguring lesions of molluscum contagiosum occurring in a 4-year-old girl secondary to a primary immunodeficiency disorder. The child, born of consanguineous parents, had multiple, asymptomatic, raised, skin-colored and whitish lesions since 2 years of age. On physical examination she had growth retardation features with grade II protein energy malnutrition. Cutaneous examination revealed numerous, widespread, skin-colored to translucent, firm, umbilicated papules of varying sizes (pinpoint to larger than 10 mm). They were distributed bilaterally over all four limbs, including the dorsum of the hands and feet, trunk, face (including lips), eyelids, auriculae, and perineal and gluteal areas. In places, they were linearly disposed and had coalesced to form plaques. A biopsy specimen from a representative skin lesion (arm) demonstrated lobulated epidermal growth consisting of keratinocytes with large intracytoplasmic eosinophilic inclusion bodies and a central crater. These findings were consistent with the diagnosis of molluscum contagiosum. Topical therapies with phenol and trichloroacetic acid were ineffective The child succumbed to a fulminant systemic infection at home, 2 months after discharge from the hospital. The extent and distribution of molluscum contagiosum in our patient was remarkably vivid and has been hitherto reported only rarely.

Atopic dermatitis and fungi

Atopic dermatitis (AD) is a chronic, itching, inflammatory skin disease which is associated with asthma and/or hay fever and a familial occurrence of these conditions. Genetic factors are important in the development of AD, but the exact hereditary pathway is still unknown. Dry skin and the weakened barrier function in patients with AD is very important for the patient's reactions to irritants and other external trigger factors including microorganisms. The standard treatments are topical corticosteroids, topical immunomodulating agents, and emollients. If AD cannot be controlled by this type of treatment, systemic immunomodulating agents may be used. UVB, UVA, or psoralen-UVA may also be used for widespread severe lesions. However, some patients do not respond to these standard treatment, and then it is important to consider the role of microorganisms, house dust mites or food. The role of the Malassezia yeasts in AD, especially AD located to the head and neck region, is now documented in several papers. There are also several papers indicating the role of Candida as an aggravating factor in AD. Patients with AD also develop chronic dermatophyte infections more easily, and patients with AD and chronic dermatophyte infections may show improvement in their AD when treated with antifungal drugs.

FcepsilonRI induces the tryptophan degradation pathway involved in regulating T cell responses

FcepsilonRI is suspected to play a pivotal role in the pathophysiology of atopic disorders such as atopic dermatitis. In search for genes differentially regulated by FcepsilonRI on APCs, a differential cDNA bank of receptor-stimulated and unstimulated monocytes was established. By means of suppression subtractive hybridization, we identified kynurenine 3-monooxygenase and subsequently indoleamine 2,3-dioxygenase (IDO) to be overexpressed in FcepsilonRI-activated monocytes. IDO is the rate-limiting enzyme in the catabolism of the essential amino acid tryptophan. We show that cross-linking of FcepsilonRI on monocytes results in low tryptophan concentrations associated with impaired T cell stimulatory capacity. Importantly, T cell suppression could be prevented by the addition of tryptophan or inhibition of IDO. Moreover, stimulation of T cells by FcepsilonRI-activated monocytes was increased compared with T cell stimulation by nonactivated monocytes if exogenous supply of tryptophan was available. We speculate that the expression of IDO by FcepsilonRI(+) APCs in vivo allows these cells to regulate T cell responses in atopic disorders by inhibiting or stimulating T cell proliferation, depending on the metabolic environment.

A review of the dermatologic manifestations of poxvirus infections

Physicians need to be familiar with the presentation of poxvirus infections. The poxvirus infections that are common, such as MCV, are rarely serious; however, physicians need to understand them because they can be bothersome to patients and require reassurance and, if available, treatment. The more rare poxvirus infections, such as variola, need to be recognized because they are generally serious. It is important to consider that these infections can suggest underlying systemic disease, as in the case of severe, recalcitrant MCV infection, which may be indicative of HIV infection or another immunocompromised state.