Wolf's Isotopic Response after Herpes Zoster Infection: A Study of 24 New Cases and Literature Review

Wolf's isotopic response refers to the occurrence of a new skin disease at the exact site of an unrelated skin disease that had previously healed. Various cutaneous lesions have been described after herpes zoster. This study included 24 patients with Wolf's isotopic response after herpes zoster infection, which presented as manifestations ranging from inflammatory disease to carcinoma. Histopathological examinations in 12 patients and immunohistochemical analyses in 10 patients allowed exploration of secondary microscopic changes in the lesions. CD4+/CD8+ T-cell ratios were normal and infiltrating cells included mast cells, eosinophils, and tumour cells. Our study has described additional patients with confirmed Wolf's isotopic response following herpes zoster infection; moreover, it has extended the spectrum of Wolf's isotopic response to include impetigo. We suggest Wolf's isotopic response classification categories for herpes zoster-associated Wolf's isotopic response. Additionally, clinicians should consider the possibilities of different diseases in Wolf's isotopic response, especially malignancies.

Topical Antibacterial Agent for Treatment of Adult and Pediatric Patients With Impetigo: Pooled Analysis of Phase 3 Clinical Trials

Ozenoxacin is a novel topical antibacterial agent with potent bactericidal activity against Gram-positive bacteria that has been developed as a 1% cream for treatment of impetigo. This article presents pooled results of pivotal clinical trials of ozenoxacin with the objective of evaluating the efficacy, safety, and tolerability of ozenoxacin 1% cream after twice-daily topical treatment for 5 days in patients with impetigo. A pooled analysis was performed of individual patient data from two multicenter, randomized, double-blind, vehicle-controlled phase 3 registration studies conducted in patients with impetigo. Both clinical trials followed a similar methodology. Patients were randomized 1:1 to ozenoxacin or vehicle. One trial included retapamulin as an internal control. Efficacy was measured using the Skin Infection Rating Scale and microbiological culture. Safety and tolerability were evaluated. Ozenoxacin demonstrated superior clinical success versus vehicle after 5 days of therapy, superior microbiological success versus vehicle after 2 days of therapy, and was safe and well-tolerated. Ozenoxacin showed superior clinical and microbiological response versus vehicle in children as young as 2 months of age, and adults, with impetigo. Clinical Trial Registration: ClinicalTrials.gov identifier: NCT01397461 and NCT02090764; European Clinical Trials Database Number: 2011-003032-31 and 2014-000228-52. J Drugs Dermatol. 2018;17(10):1051-1057.

Recurrent impetigo herpetiformis: case report

Impetigo herpetiformis (pustular psoriasis of pregnancy) is a rare dermatosis of pregnancy that typically starts in the 2nd half of pregnancy and resolves postpartum. It may recur in subsequent pregnancies. I present a case of 23 year old female gravida 4 para 3 with recurrent impetigo herpetiformis at 26 weeks gestation. She presented with a one month history of pustular lesions which responded to treatment with prednisone. She delivered at term with a favourable outcome. The disease resolved one month postpartum. This was the second recurrence of the disease. She had her first episode of impetigo herpetiformis during the second pregnancy. The disease recurred in the 3rd pregnancy and resulted in a still birth.

Concurrent pyogenic granuloma and bullous impetigo of a pregnant woman's finger

BACKGROUND

Bullous impetigo is a superficial skininfection caused by Staphylococcus aureus (S.aureus). Pyogenic granuloma is a common benigntumor frequently associated with prior trauma.Bullous impetigo and pyogenic granuloma may occurin pregnant women.

PURPOSE

The features of a pregnant womanwith pyogenic granuloma and bullous impetigoconcurrently present in a lesion on her finger aredescribed.

METHODS

PubMed was used to search the followingterms: bullous impetigo, pregnancy, and pyogenicgranuloma. All papers were reviewed; relevantarticles, along with their references, were evaluatedResults: A red ulcerated nodule with a collaretteof epithelium around the tumor and surroundingbullae appeared on the fifth digit of the left hand of a31-year-old woman who was at 36 weeks gestation. Abacterial culture grew methicillin sensitive S. aureus.An excisional biopsy was performed. Histologicfindings revealed not only a benign vascular tumorwith an infiltrate of mixed inflammatory cells, butalso an intraepidermal blister. She received oralantibiotics and there was complete resolution of thefinger lesion and infection with preservation of digitfunction.

CONCLUSION

Albeit uncommon, pyogenic granulomaand bullous impetigo may concurrently occur in thesame lesion. Therapeutic intervention should focuson treating both the benign skin tumor and theinfection.

[A neonate with blisters on his upper legs]

A 10-days-old male neonate presented with multiple bullae, mostly in the diaper region, without signs of illness. We diagnosed this condition as neonatal bullous impetigo and treated the patient orally with flucloxacillin. Bullous impetigo is caused by Staphylococcus aureus toxins that break down intercellular proteins.

Diffuse alveolar hemorrhage in a patient with acute poststreptococcal glomerulonephritis caused by impetigo

We herein report a case of pulmonary renal syndrome with nephritis in a 17-year-old boy with diffuse alveolar hemorrhage (DAH) associated with acute poststreptococcal glomerulonephritis (APSGN). The patient exhibited hemoptysis two weeks after developing impetigo, and DAH was diagnosed on bronchoscopy. Respiratory failure progressed, and high-dose methylprednisolone therapy was administered; the respiratory failure regressed immediately after the onset of therapy. Streptococcus pyogenes was detected in an impetigo culture, and, together with the results of the renal biopsy, a diagnosis of APSGN was made. This case demonstrates the effects of high-dose methylprednisolone therapy in improving respiratory failure.

Standardising and assessing digital images for use in clinical trials: a practical, reproducible method that blinds the assessor to treatment allocation

With the increasing availability of high quality digital cameras that are easily operated by the non-professional photographer, the utility of using digital images to assess endpoints in clinical research of skin lesions has growing acceptance. However, rigorous protocols and description of experiences for digital image collection and assessment are not readily available, particularly for research conducted in remote settings. We describe the development and evaluation of a protocol for digital image collection by the non-professional photographer in a remote setting research trial, together with a novel methodology for assessment of clinical outcomes by an expert panel blinded to treatment allocation.

Topical Antibiotic Treatment of Impetigo with Tetracycline

Forty-nine children aged 0.2-13 years with bullous and eroded lesions, from which Staphylococcus aureus was isolated, were diagnosed with impetigo and entered into a randomized, open-labeled trial of topical oxytetracycline hydrochloride (tetracycline) compared with a combination of topical tetracycline and oral antibiotics. After one week of topical tetracycline treatment, 22 of the 28 patients were clinically cured, and the remaining six patients had improved. In the other treatment group, 14 patients of 21 were clinically cured and 7 patients improved by the combination of topical tetracycline and oral antibiotics. There were no significant differences between the two groups. Therefore, the present study suggests that topical tetracycline treatment is effective for the treatment of impetigo.

Bullous impetigo associated with Abiotrophia defectiva in an immunocompetent adult

Infection of humans by Abiotrophia defectiva, a nutritionally variant streptococcus, most commonly takes the form of endocarditis, though a variety of other manifestations ranging from central nervous system abscesses to orthopaedic infections have been seen. We report here what we believe is the first case of bullous impetigo associated with this organism.

NVC-422 topical gel for the treatment of impetigo

Impetigo is a highly contagious bacterial skin infection affecting children worldwide that is caused by the Gram-positive bacteria Staphylococcus aureus, Streptococcus pyogenes, or both. Staphylococcus species can quickly develop drug resistance rendering mupirocin, fusidic acid, and erythromycin ineffective. Preclinical and clinical studies demonstrated that NVC-422 (N, N-dichloro-2, 2-dimethyltaurine) rapidly kills pathogens without the development of drug resistance. 129 patients with clinically diagnosed impetigo were randomized to three dose groups (0.1, 0.5, or 1.5% NVC-422 topical gel) in a study conducted at 2 centers; 125 patients (97%) had microbiologically confirmed infection. Treatment was administered three times a day (TID) for 7 days to all randomized subjects. Response was measured at the completion of treatment (Day 8) and 1 week post treatment (Day 15) by the Skin Infection Rating Scale (SIRS) and by microbiological response. A total of 120 subjects (96%) completed all 7 days of treatment and were assessed at end of treatment (EOT). Clinical response rate at EOT in the PPC population was excellent in each of the dose groups (84.6%, 87.2%, and 92.3% in the 0.1%, 0.5% and 1.5% dose groups respectively). The majority of the infections were caused by S. aureus, alone (106/125, 85%) of which approximately 10% were MRSA. There were no clinical recurrences in any treatment groups. Treatment-emergent adverse events were seen in 5.4% of the subjects (7/129) and were mild to moderate and resolved. NVC-422 topical gel administered TID was well tolerated, with high rates of clinical and microbiological responses for treating impetigo.

Blistering skin conditions

BACKGROUND

Blistering of the skin can be due to a number of diverse aetiologies. Pattern and distribution of blisters can be helpful in diagnosis but usually biopsy is required for histopathology and immunofluoresence to make an accurate diagnosis.

OBJECTIVE

This article outlines the clinical and pathological features of blistering skin conditions with a particular focus on bullous impetigo, dermatitis herpetiformis, bullous pemphigoid and porphyria cutanea tarda.

DISCUSSION

Infections, contact reactions and drug eruptions should always be considered. Occasionally blistering may represent a cutaneous manifestation of a metabolic disease such as porphyria. Although rare, it is important to be aware of the autoimmune group of blistering diseases, as if unrecognised and untreated, they can lead to significant morbidity and mortality. Early referral to a dermatologist is important as management of blistering skin conditions can be challenging.

Impetigo herpetiformis occurring during N-butyl-scopolammonium bromide therapy in pregnancy: case report

Impetigo herpetiformis (IH) is a rare dermatosis arising during the third trimester of pregnancy which is generally considered as a form of pustular psoriasis of unknown aetiology. Clinically it is characterized by erythematous plaques surrounded by sterile pustules associated with fever, diarrhea, sweating and increasing risk of stillbirth for placental insufficiency. We describe a case of developed erythematous plaques surrounded by pustules localised initially to the trunk of a 35-year-old woman at the 34th week of gestation after 5 days of treatment with N-Butyl-Scopolammonium, and which later involved the upper and lower limbs. Skin histology confirmed the diagnosis of generalised pregnancy pustular psoriasis (impetigo herpetiformis). IH is reported to be associated with hypocalcemia, hypoparathyroidism, use of oral contraceptives and bacterial infections. This is the first report suggesting the potential role of drugs other than oral contraceptives in the pathogenetic mechanism of this disease. In this case an adverse cutaneous reaction to BB could be the cause of the development of Koebner isomorphism.

Staphylococcal exfoliative toxins: “Molecular scissors” of bacteria that attack the cutaneous defense barrier in mammals

Bullous impetigo and its generalized form, staphylococcal scalded-skin syndrome (SSSS), are highly contagious, blistering skin diseases caused by Staphylococcus aureus infection. Virulent strains of the bacteria produce exfoliative toxins (ETs) that cause the loss of keratinocyte cell-cell adhesion in the superficial epidermis. Recent studies have indicated that the three isoforms of ETs, i.e., ETA, ETB, and ETD, are glutamate-specific serine proteases that specifically and efficiently cleave a single peptide bond in the extracellular region of human and mouse desmoglein 1 (Dsg1), a desmosomal intercellular adhesion molecule. In addition, four isoforms of S. hyicus exfoliative toxin, ExhA, ExhB, ExhC, and ExhD, cleave swine Dsg1, resulting in skin exfoliation similar to that observed in pigs with exudative epidermitis. In this review, we describe recent advances in our knowledge of the mechanisms of action of staphylococcal exfoliative toxins, which act as "molecular scissors" to facilitate percutaneous bacterial invasion of mammalian skin by cleavage of keratinocyte cell-cell adhesion molecules. The species-specificity of staphylococcal exfoliative toxins to cleave Dsg1 in certain mammalian species is discussed.

Retapamulin: a semisynthetic pleuromutilin compound for topical treatment of skin infections in adults and children

Retapamulin is a semisynthetic pleuromutilin compound with in vitroactivity against Gram-positive bacteria, no cross-resistance to other classes of antimicrobial agents in current use and a low potential for development of resistance. A 1% ointment formulation has been developed for clinical use, and a placebo-controlled trial of impetigo in 210 patients produced significantly higher rates of clinical and microbiological success compared with placebo - 85.6 versus 52.1% and 91.2 versus 50.9%, respectively. Additional comparative studies in over 1900 patients showed noninferiority to topical fusidic acid and oral cephalexin and a low frequency of adverse events. In 2007, retapamulin was approved in the USA for topical treatment of impetigo caused by Streptococcus pyogenes and methicillin-susceptible Staphylococcus aureus, and in the EU for topical treatment of impetigo and infected wounds caused by S. pyogenes and S. aureus, with approvals including adults and children over 9 months of age.

Topical Retapamulin Ointment, 1%, versus Sodium Fusidate Ointment, 2%, for Impetigo: A Randomized, Observer-Blinded, Noninferiority Study

BACKGROUND

Retapamulin is a novel pleuromutilin antibacterial developed for topical use.

OBJECTIVE

To compare the efficacy and safety of retapamulin ointment, 1% (twice daily for 5 days), with sodium fusidate ointment, 2% (3 times daily for 7 days), in impetigo.

METHODS

A randomized (2:1 retapamulin to sodium fusidate), observer-blinded, noninferiority, phase III study in 519 adult and pediatric (aged > or = 9 months) subjects.

RESULTS

Retapamulin and sodium fusidate had comparable clinical efficacies (per-protocol population: 99.1 and 94.0%, respectively; difference: 5.1%, 95% confidence interval: 1.1-9.0%, p = 0.003; intent-to-treat population: 94.8 and 90.1%, respectively; difference: 4.7%, 95% confidence interval: -0.4 to 9.7%, p = 0.062). Bacteriological efficacies were similar. Success rates in the small numbers of sodium-fusidate-, methicillin- and mupirocin-resistant Staphylococcus aureus were good for retapamulin (9/9, 8/8 and 6/6, respectively). Both drugs were well tolerated.

CONCLUSION

Retapamulin is a highly effective and convenient new treatment option for impetigo, with efficacy against isolates resistant to existing therapies.

A case of impetigo herpetiformis associated with intrahepatic cholestasis of pregnancy

We herein reported a 26-year-old primigravida with impetigo herpetiformis and intrahepatic cholestasis of gestation. She was in gestation for 34 weeks. She had a 5-month history of pustules on the trunk and limbs that had exacerbated from 1 month before. The jaundice had also emerged lately with increased levels of serous transaminase, bilirubin and bile acid. The histopathology of the lesion confirmed the diagnosis of impetigo herpetiformis. After cesarean section and administration of glucocorticoid, the patient totally recovered.

Facial and perioral primary impetigo: a clinical study

Impetigo is the most common skin infection in children. The face, especially the perioral region, is one of the most frequently involved areas. Impetigo is a disease that interests the pediatric dentist, as it poses significant problems in its differential diagnosis from other conditions. Sixteen otherwise healthy children were examined suffering from facial and perioral impetigo. The typical clinical appearance was scattered, painless, slightly pruritic erosions covered by "honey-colored" crusts. In 4 children impetigo was localized in the facial and perioral area, whereas in all other cases lesions were diffused in perioral area and several regions throughout the body. Four children exhibited neck lymphadenopathy and one had mild fever. The treatment of impetigo included the application of topical measures with the systemic antibiotic chemotherapy.

Impétigo herpétiforme et syndrome d’Ondine

INTRODUCTION

Impetigo herpetiformis is a rare dermatitis that occurs during pregnancy and may be life threatening for both mother and child. In this case report, we present an Ondine curse involving the baby, and the good response to isotretinoine.

CASE REPORT

A first pregnancy, 26 year-old woman developed at 8 months a widespread skin lesion involving the medial side of the thighs, abdomen and intertriginous areas, with a severe systemic toxic condition and fever. Diagnosis of impetigo herpetiformis was made and corticosteroids, methotrexate and cyclosporine were unsuccessful. Isotretinoine rapidly improved the patient with good control of the disease. The full term baby had an Ondine curse.

DISCUSSION

Our case is typical of impetigo herpetiformis. Maternal and infant complication may be life threatening and we report a real Ondine curse the etiology of which remains unknown. Moreover, this observation is unusual because the lesions did not clear despite delivery and good treatment. In our opinion, the great improvement with isotretinoine would suggest it could be used as first line treatment.

Treatment of bullous impetigo and the staphylococcal scalded skin syndrome in infants

Impetigo is a common, superficial, bacterial infection of the skin characterized by an inflamed and infected epidermis. The rarer variant, bullous impetigo, is characterized by fragile fluid-filled vesicles and flaccid blisters and is invariably caused by pathogenic strains of Staphylococcus aureus. Bullous impetigo is at the mild end of a spectrum of blistering skin diseases caused by a staphylococcal exfoliative toxin that, at the other extreme, is represented by widespread painful blistering and superficial denudation (the staphylococcal scalded skin syndrome). In bullous impetigo, the exfoliative toxins are restricted to the area of infection, and bacteria can be cultured from the blister contents. In staphylococcal scalded skin syndrome the exfoliative toxins are spread hematogenously from a localized source causing widespread epidermal damage at distant sites. Both occur more commonly in children under 5 years of age and particularly in neonates. It is important to swab the skin for bacteriological confirmation and antibiotic sensitivities and, in the case of staphylococcal scalded skin syndrome, to identify the primary focus of infection. Topical therapy should constitute either fusidic acid (Fucidin, Leo Pharma Ltd) as a first-line treatment, or mupirocin (Bactroban, GlaxoSmithKline) in proven cases of bacterial resistance. First-line systemic therapy is oral or intravenous flucloxacillin (Floxapen, GlaxoSmithKline). Nasal swabs from the patient and immediate relatives should be performed to identify asymptomatic nasal carriers of Staphylococcus aureus. In the case of outbreaks on wards and in nurseries, healthcare professionals should also be swabbed.

Pustular impetigo with good response to clarithromycin

Impetigo is a contagious superficial pyogenic infection of the skin caused by Staphylococcus aureus and/or by group A Streptococcus. Two main clinical forms are recognized: bullous impetigo and non-bullous impetigo. We present an unusual case of pustular impetigo in a 35-year-old man. The pustules were localized symmetrically in the groin and the patient was successfully treated with clarithromycin. In bullous impetigo, exfoliative toxins produced by Staphylococcus aureus are accepted as the basis for the bulla formation just below the stratum granulosum. Although clarithromycin is considered to be a second-choice therapy for bullous impetigo, it was highly effective in our case.

Assessment of Streptococcus pyogenes microcolony formation in infected skin by confocal laser scanning microscopy

BACKGROUND

Streptococcus pyogenes and Staphylococcus aureus are often simultaneously detected from many cases of non-bullous impetigo with atopic dermatitis.

OBJECTIVES

Using confocal laser scanning microscopy (CLSM), to investigate formation of S. pyogenes microcolonies in skin lesions.

METHODS

The S. pyogenes cells in the stationary growth phase alone were strongly stained with fluorescein isothiocyanate-concanavalin A (FITC-ConA), and this staining was reduced by pretreatment with amylase. Although the components of sugars in glycocalyx produced by S. pyogenes cells are unknown, we suggested that the materials stained by FITC-ConA were consistent with the presence of ConA-reactive sugars in glycocalyx produced by S. pyogenes cells.

RESULTS

S. pyogenes cells associated with streptococcal impetigo skin and croton-oil inflamed mouse skin formed microcolonies encircled by materials (glycocalyx) that stained strongly with FITC-ConA, and these findings were consistent with those in biofilms. In croton-oil inflamed mouse skin, polymorphonuclear leukocytes (PMNs) infiltrated to just below the epidermis in the cefdinir-treated group but only to the middle dermis in the cefdinir-non-treated group. In this case S. pyogenes and S. aureus cells formed separate microcolonies and existed independently in the outer walls of pustule lesions of streptococcal impetigo.

CONCLUSION

In skin infections, S. pyogenes and S. aureus formed aggregates of microcolonies (similar to that in biofilms) encircled by glycocalyx, which can make the infection hard to eradicate using an antimicrobial agent alone. The effect of conventional antimicrobial agents against biofilm is mainly due to the increase of the invasion of PMNs into the biofilm.

The pustular disorders

The pustular disorders constitute a subgroup of the vesiculobullous disorders defined by the presence of eosinophils or neutrophils with prominent accompanying intercellular edema or a canthelysis involving various levels of the epithelium. Herein, we describe the clinical and pathologic attributes of the subcorneal, infectious, neonatal, papulosquamous, drug-induced and miscellaneous pustular conditions.

What's your assessment?

The "What's Your Assessment?" series includes a short case presentation and differential diagnosis. It is followed by a discussion of the disease or condition and the rationale used in each step of the assessment.

Differential pathomechanisms of epidermal necrolytic blistering diseases

Staphylococcal scalded skin syndrome (SSSS) results from the effect of exfoliative-toxins produced by staphylococcal strains. The disease affects predominantly children, and is rare in adults. We report two cases of the adult type of SSSS. Corticotherapy, chronic alcohol abuse and epilepsy-related immune changes might have been predisposing factors in these patients. The immunopathological characteristics of the inflammatory cell infiltrate in adults SSSS have not been thoroughly explored so far in the literature. Biopsies from 2 patients with bullous SSSS skin were studied by means of immunochemistry using a panel of 10 antibodies directed to FXIIIa, CD15, CD31, CD45R0, CD50, CD54, CD62E, CD95, CD106, and L1-protein, respectively. Cutaneous biopsies from related blistering diseases were compared. They included drug-induced toxic epidermal necrolysis (TEN), bullous impetigo and superficial pemphigus. A dense cell infiltrate composed of granulocytes (CD15+), macrophages (L1 protein+) and memory T cells (CD45R0+) and a strong expression of ICAM-3 (CD50) were present in the epidermis. CD95+ keratinocytes were lining the intraepidermal blisters. Type I dermal dendrocytes (Factor XIIIa+) were numerous and plump in the dermis. Bullous impetigo exhibited the same pattern of inflammatory cells, but with a lower density in type I dermal dendrocytes. TEN differed from SSSS by both the absence of CD15+ granulocytes and a stronger expression of the pro-apoptotic CD95 antigen in the epidermis. In superficial pemphigus, CD95 antigen was not expressed, and CD15+ granulocytes, CD45R0+ lymphocytes and L1 protein+ monocytes were much less numerous. It is concluded that the specific binding of SSSS-induced exotoxins to the desmosomes alters the keratinocyte metabolism leading to an inflammatory reaction followed by focal apoptosis. Our findings are in line with the concept that SSSS exotoxins might be superantigens. A common pathomechanism leading to epidermal destruction is likely operative in SSSS and bullous impetigo. The inflammatory cell composition in TEN and superficial pemphigus markedly differs from that in SSSS.

Recurrent impetigo herpetiformis in a pregnant adolescent: case report

Impetigo Herpetiformis is a rare pustular dermatosis that typically occurs in pregnant women with unknown etiology. A 17 year old patient who developed Impetigo Herpetiformis for the second time in the 27th week of her 2nd pregnancy is presented. The patient improved with corticosteroids treatment but the lesions did not clear completely and had flare ups during stressful periods which brings us to conclusion that Impetigo Herpetiformis at least has a common pathway with Generalized Pustular Psoriasis in the pathogenesis as stress provoked exacerbations.

[Streptococcus group A infections of skin, soft tissue and blood]

BACKGROUND

Group A streptococcus is one of the most common bacterial pathogens causing infections in tissue and organs, most frequently throat and skin. Since the late 1980s there have been reports from Scandinavia and many other countries documenting a resurgence of highly invasive infections such as puerperal fever, necrotizing fasciitis, myositis and sepsis.

MATERIAL AND METHODS

On the basis of relevant studies and reviews and a clinical study of 61 patients between 1992 and 1999 with necrotizing fasciitis and myositis at Haukeland University Hospital, Bergen, Norway, we present an overview of the prevalence, pathogenesis, clinical features and treatment of group A streptococcal infections in skin, soft tissue and blood.

RESULTS AND INTERPRETATION

The reason for the increase in severe group A streptococcal infections is unclear. The clinical features depend on the level of infection (superficial skin, subcutis, fascia and muscle): the deeper the initial infection, the more frequent development of bacteraemia and life-threatening disease. Serious infections are associated with shock and multiorgan failure, i.e. streptococcal toxic shock syndrome. Early surgical debridement is essential in necrotizing fasciitis and myositis. Penicillin is still the drug of choice for milder infections. The addition of clindamycin is recommended in cases of more invasive infection.

Toxin in bullous impetigo and staphylococcal scalded-skin syndrome targets desmoglein 1

Exfoliative toxin A, produced by Staphylococcus aureus, causes blisters in bullous impetigo and its more generalized form, staphylococcal scalded-skin syndrome. The toxin shows exquisite specificity in causing loss of cell adhesion only in the superficial epidermis. Although exfoliative toxin A has the structure of a serine protease, a target protein has not been identified. Desmoglein (Dsg) 1, a desmosomal cadherin that mediates cell-cell adhesion, may be the target of exfoliative toxin A, because it is the target of autoantibodies in pemphigus foliaceus, in which blisters form with identical tissue specificity and histology. We show here that exfoliative toxin A cleaved mouse and human Dsg1, but not closely related cadherins such as Dsg3. We demonstrate this specific cleavage in cell culture, in neonatal mouse skin and with recombinant Dsg1, and conclude that Dsg1 is the specific receptor for exfoliative toxin A cleavage. This unique proteolytic attack on the desmosome causes a blister just below the stratum corneum, which forms the epidermal barrier, presumably allowing the bacteria in bullous impetigo to proliferate and spread beneath this barrier.

Generalized pustular psoriasis of pregnancy (impetigo herpetiformis)

A 17-year-old woman had a sudden eruption of pustules in her intertriginous areas as well as of erythematosquamous plaques on the scalp, elbows, palms and soles in the third trimester of her first pregnancy. Histopathological evaluation of a biopsy revealed typical changes of pustular psoriasis with parakeratosis and abscesses of neutrophils (Kogoj's spongiform pustules). The diagnosis of pustular psoriasis was established by the typical clinical and histopathological findings. Laboratory parameters showed a highly elevated blood sedimentation rate, hypoferric anemia and decreased albumin levels. Serum concentrations of parathormone and its metabolites were normal. After systemic treatment with glucocorticosteroids and antibiotics, the lesions improved but did not clear. After delivery of a healthy boy, therapy was switched to retinoid photochemotherapy with isotretinoin and PUVA that resulted in rapid and complete clearing of the eruption. The coincidence of plaque-type psoriasis and a pustular eruption as described previously in impetigo herpetiformis supports the view that this dermatosis of pregnancy is a variant of generalized pustular psoriasis.

Humanized in vivo model for streptococcal impetigo

An in vivo model for group A streptococcal (GAS) impetigo was developed, whereby human neonatal foreskin engrafted onto SCID mice was superficially damaged and bacteria were topically applied. Severe infection, indicated by a purulent exudate, could be induced with as few as 1,000 CFU of a virulent strain. Early findings (48 h) showed a loss of stratum corneum and adherence of short chains of gram-positive cocci to the external surface of granular keratinocytes. This was followed by an increasing infiltration of polymorphonuclear leukocytes (neutrophils) of mouse origin, until a thick layer of pus covered an intact epidermis, with massive clumps of cocci accumulated at the outer rim of the pus layer. By 7 days postinoculation, the epidermis was heavily eroded; in some instances, the dermis contained pockets (ulcers) filled with cocci, similar to that observed for ecthyma. Importantly, virulent GAS underwent reproduction, resulting in a net increase in CFU of 20- to 14,000-fold. The majority of emm pattern D strains had a higher gross pathology score than emm pattern A, B, or C (A-C) strains, consistent with epidemiological findings that pattern D strains have a strong tendency to cause impetigo, whereas pattern A-C strains are more likely to cause pharyngitis.

Impetigo herpetiformis during the puerperium

We report on a 29-year-old primigravida who developed impetigo herpetiformis 1 day after delivery. To our knowledge, this patient is the second reported case of impetigo herpetiformis presenting during the puerperium. The patient responded quickly to systemic administration of methotrexate and prednisolone.

Increasing incidence of streptococcal impetigo in atopic dermatitis

Streptococcal impetigo associated with atopic dermatitis has dramatically increased from 1989 to 1994 in outpatients visiting our hospital, totalling 174 cases. The most frequent causative agents were group A streptococci (Streptococcus pyogenes, 70.7%) followed by group G (19.5%) and group B (9.8%). Streptococcus was isolated singly in 28.2% of cases and in concomitant with Staphylococcus aureus (S. aureus) in 71.8%. Major clinical features of streptococcal impetigo, especially caused by group A streptococci, were non-bullous pustules with thick crusted ceiling. Impetigo caused by group G or B streptococci generally formed smaller sized pustules of fewer numbers. Impetigo was usually present, associated with severe eczematous lesions. Various degrees of fever were noticed in 32.8% (group A, 39.8%; group G, 17.6%; group B, 11.8%) during active stages. The lesions on the face often resembled Kaposi's varicelliform eruption in any group. Systemic antimicrobial agents were administered in 71.3% of cases and the remainder were treated with topical antibiotics (oxytetracycline hydrochloride) or disinfectants (povidone-iodine). Recurrence occurred within a month in 38.0% of cases treated with topical agents only and in 17.7% treated with systemic antimicrobial agents. Antimicrobial susceptibility tests and the results of treatment seem to indicate that cephems, as well as penicillins, are the first choice of treatment for streptococcal impetigo.

[Erysipelas and impetigo]

Erysipela is a dermal or hypodermal infection of the skin, which predominantly involves the leg and is associated with high fever. Erysipela is most often caused by Streptococcus pyogenes. Venous insufficiency or lymphoedema are important local factors for the development of this infection which spreads from intertrigo, local wound or leg ulcer. Treatment is essentially based on parenteral penicillin G. Impetigo is a superficial infection of the skin due to Staphylococcus aureus or to Streptococcus pyogenes, and is frequent in children. Classical impetigo is made of yellow-brown crusts located around the mouth and nose, whereas bullous impetigo involves frequently the trunk and limbs. Secondary impetigo occurring in pediculosis or scabiosis is frequent. It is a contagious disease which is more frequent in patients with poor hygiene. It can be treated by general antibiotics, mainly macrolides, penicillin M or cephalosporins.

[Child abuse caused by thermal violence--determination and reconstruction]

Problems in the judgement of child abuse due to thermal violence are discussed by means of two examined cases. In a baby dermal lesions in the course of a bacterial infectious disease (bullous impetigo) were first misinterpreted as heat effects (cigarette, hot instrument). In the case of an infant presenting with marked imprints of a hot iron abuse was to be differentiated versus an accidental causation.

CONCLUSIONS

In the interpretation of possible thermal injuries in children natural preexisting disorders of the skin should be taken into consideration. In cases of doubt an appropriate clinical diagnosis or a subsequent follow-up examination, respectively, is recommended. Thus, the course of events can be observed and an unjustified incrimination of persons having custody is avoided.

Hydrogen peroxide cream: an alternative to topical antibiotics in the treatment of impetigo contagiosa

In total, 256 patients with bacteriologically verified impetigo contagiosa were included in three double-blind, parallel group, randomized, multi-centre trials, where the efficacy of hydrogen peroxide cream (Microcid) was compared with that of fusidic acid cream/gel (Fucidin). The trials were performed at 47 centres in three countries, Sweden, Germany and UK, and the results are compiled in the present report. During the course of the 3-week treatment period, 92 patients out of 128 (72%) in the Microcid group were classified as healed, compared to 105 patients out of 128 (82%) in the Fucidin group. This difference was not statistically significant. The reduction in composite sign severity score (the sum of the score for erythema, vesiculation/bullae, weeping and crusting divided by four) in each separate study was 73%, 78% and 84% in the Microcid group and 85%, 85% and 84% in the Fucidin group. No statistically significant differences were found in the separate studies or when compiling the studies in a meta-analysis. When the patients had been classified as healed, beta-haemolytic streptococci were eliminated in all patients treated with Microcid cream. Since treatment started before the result of the bacteriology was known, another 135 patients with negative skin culture were enrolled in the trials, i.e. 391 patients were included in the safety analysis. Out of these, 23 patients reported the occurrence of adverse events, mainly classified as mild. In conclusion, Microcid cream has been documented as a topical alternative to fusidic acid in the treatment of impetigo.

Production of staphylococcal impetigo-like lesion on human skin explants in culture

We produced a highly reproducible experimental impetigo-like lesion in normal human skin explants in culture. The three Staphylococcus aureus strains we used were an isolate from a human impetigo (E strain), an isolate from a human furunculosis (N strain) and ATCC 29213 strain. E strain was a protein A positive, coagulase type V, producer of exfoliative toxin (ET) and beta-toxin. N strain was a coagulase type IV, ET non-producer and alpha-toxin positive. ATCC 29213 was a coagulase type II, ET non-producer, and alpha-, beta-, and delta-toxin positive. Normal human skin samples were obtained from 8 adult skin surgery patients. One specimen was obtained from human oral mucosa. Small pieces of the samples were slightly abraded on the epidermal surface and cultured on lens paper rafts floating in Eagle's Minimum Essential Medium in an atmosphere of 5% CO2 and 95% air. Fifty microliters of the respective bacterial suspensions were applied to the epidermal surfaces of the explants. The inoculated surfaces were then occluded under sterile plastic plaster. Histologically, the formation of intraepidermal blisters at the granular layer level with acantholytic cells was observed in all 8 of the skin specimens at 10 h after inoculation with E strain. The specimen from an oral mucous membrane did not produce similar changes with any of the three S. aureus strains. Neither N or ATCC strains developed bullae in the epidermis at 6, 10 or 18 h after inoculation. Immunofluorescent examination revealed that the inner surfaces of blisters in the epidermis were lined with anti-ETA antibody. Under the electron microscope, the blisters of the specimens which had been inoculated with strain E contained only a few S. aureus cells. These results suggest that blister formation at the granular layer level with acantholytic cells is mediated by ET action at the granular layer level and occurs without invasion of lymphocytes or neutrophils, or the involvement of any serum components. Therefore, under appropriate conditions, impetigo could develop even in adults.

Impetigo:an assessment of etiology and appropriate therapy in infants and children

We found that mixed organisms of S.aureus and GABHS were the most common cause of impetigo in children in our study; that, of the two regimens evaluated, cloxacillin is the most effective treatment; that penicillin is equally effective in cases of mild to moderate forms and may be preferred on the basis of cost-effectiveness.

Production of experimental staphylococcal impetigo in mice

We produced a staphylococcal impetigo model by epicutaneous inoculation in mature mice. A strain isolated from a human impetigo was used. Five-week-old female mice (ddy-strain) were used with and without pre-treatment by cyclophosphamide (Cy) (2 mg/mouse) for 5 days. The back skin of mice was shaved by a razor blade and slightly abraded by sand paper. Bacterial suspension (1.4 x 10(7) CFU/0.05 ml) was applied on the abraded areas which were then occluded under sterile plastic plaster. Although intraepidermal blisters developed in non-Cy-treated mice, massive neutrophil infiltration obscured the changes there. Development of subcorneal bullae in Cy-treated mice inoculated with Staphylococcus aureus was first observed at 3h and enlargement of bullae was apparent at 12 h after inoculation. The bullae produced in Cy-treated mice contained numerous S. aureus bacilli. Electronmicroscopically, S. aureus cells invaded the horny layer at 1/4 h. A clear halo was seen between S. aureus cells and horny cells. S. aureus cells attached to surrounding horny cells by fibril-like structures. The halo-like spaces became larger, coalesced and then developed into an intraepidermal blister. Our new method to produce human impetigo-like blister in Cy-treated adult mice may contribute to disclosing the mechanisms of blister formation in epidermis by S. aureus. Due to the thin structure of mouse epidermis, only specimens taken earlier than 24 h after inoculation were considered appropriate.