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We report a 14-month-old White boy who was referred to our dermatology unit for evaluation of a skin eruption on his nose. The initial examination led us to the clinical diagnosis of impetigo. The mycologic studies found an uncommon dermatophyte agent, Microsporum gypseum. The main differential diagnosis of tinea faciei is discussed.
Typical pustular lesions of impetigo herpetiformis were examined by electron microscopy. In the upper layers of the epidermis degenerated keratinocytes and neutrophils lay close together and amorphous substances were seen within and outside the keratinocytes. Neutrophiles were not observed within the keratinocytes. The spongiform pustules of Kogoj observed with light microscopy were made up of a large number of neutrophils in a network of degenerated and stretched-out keratinocytes. Amorphous masses of high electron density which seemed to represent highly degenerated keratinocytes were observed among neutrophils.
Four strains of Staphylococcus aureus of a phage type other than the second group, isolated from patients with impetigo and Ritter's disease, were found to produce an exotoxin similar to those reported by Melish et al. (1972), Kapral and Miller (1971), and Arbuthnott et al. (1973). This toxin could elicit a general exfoliation of the epidermis with the so-called Nikolsky sign when subcutaneously inoculated into neonatal mice within 4 days after birth. The new toxin was serologically different from exfoliatin produced by the phage group II staphylococci previously reported (Kondo et al., 1973) and showed an electrophoretic pattern corresponding to that of the B-type toxin of the latter in acrylamide disc electrophoresis. It had the same molecular weight as that of the latter, which was estimated to be about 24,000. It was thermolabile and lost its toxic activity by heating at 60 C for 30 min; in addition, most of the toxicity was lost within 1 month of storage even at -30 C. We propose to designate the old typical heat-stable exfoliatin as S. aureus exfoliatin A and the new heat-susceptible exfoliatin as S. aureus exfoliatin B.
Various cellular responses to skin infections in an experimental animal model were explored. Total leukocyte counts varied after group A streptococcal infections, but a depression was commonly seen after M type 12 impetigo. Staphylococcus aureus infections resulted in moderate leukocytosis. A marked neutrophilia was universal with streptococcal or staphylococcal disease. A positive nitroblue tetrazolium (NBT) response appeared 24 hr after infection, reached a peak in 48 hr, and then declined. This occurred in the absence of extensive cellulitis or bacteremia. An increase in the percentage and absolute number of NBT-positive neutrophils occurred. M type 57 streptococcus produced a more strongly positive NBT test than did M type 12. Cell-free filtrates of a broth culture of M type 57 streptococcus produced NBT responses in hamsters comparable to the responses seen after injection of live organisms. These studies indicate the usefulness of this animal model to study various parameters of the NBT test.
Group A streptococci can be classified according to their tendency to cause either impetigo, pharyngitis, or both types of infection. Genotypic markers for tissue site preference lie within emm genes, which encode fibrillar surface proteins that play a key role in virulence. emm gene products (M and M-like proteins) display an extensive array of binding activities for tissue and plasma proteins of the human host. In a previous study, a high-affinity binding site for human plasmin(ogen) was mapped to the emm53 gene product. In this report, a structurally similar plasminogen-binding domain is found to be widely and selectively distributed among group A streptococci harboring the emm gene marker for the skin as the preferred tissue site for infection. The findings are highly suggestive of a central role for bacterial modulation of host plasmin(ogen) during localized infection at the epidermis.
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.
Anticardiolipin (aCL) antibodies have been described in diverse clinical situations, linked to the risk of thrombosis in different vascular locations. They have been rarely studied in renal diseases, and occasionally they have been associated with glomerular thrombosis. We analyzed the incidence of aCL (isotypes IgG, IgA, and IgM) in samples, taken during the acute phase of the disease, from 27 well-documented patients having acute poststreptococcal glomerulonephritis. Twelve cases were positive on IgG testing, 1 case on IgA testing only, and no one was positive on IgM testing. A serological follow-up was performed with a second sample taken about 7 months later, for the patients initially positive on IgG testing showing persistence in 9. Clinical variables during the acute phase and after a follow-up period of 25 (range 6-89) months were analyzed for possible associations with the presence of these antibodies, but non was significantly related. Renal histopathological investigation did not reveal particular findings in the aCL-positive patients, and glomerular thrombosis was not found in any case. In addition, serum samples from 12 streptococcal impetigo patients without renal involvement were analyzed, showing similar incidence (4 positive on IgG testing, 1 of them positive on IgM testing as well, and no one positive on IgA testing) and titers of aCL antibodies. We conclude that the presence of aCL antibodies in acute poststreptococcal glomerulonephritis may be a marginal immunological phenomenon unrelated to the glomerular disease, triggered by the streptococcal infection.
A patient with an unusual form of follicular impetigo, who later developed classical systemic lupus erythematosus (SLE) is described. When she had pyoderma, direct immunofluorescence and serology already suggested a connective tissue disease. Pyoderma could have been the presenting manifestation of SLE.
The appearance on and spread of Group A streptococci among different body sites in relationship to the development of impetigo were studied prospectively in 31 children in five families. During July and August 1969 intensive clinical, bacteriological, and serological observations were made, including cultures taken at least every other day. In individual children, site sequence of spread of Group A streptococci was from normal skin to lesions and finally to respiratory tract. Streptococci were recovered from normal skin before development of lesions (mean interval of 10 days) in 74% of episodes. Recovery of streptococci from nose and throat followed (by means of 14 and 20 days, respectively) skin acquisition of streptococci (97% of episodes) and lesions (74% of episodes).Distribution of positive normal skin sites among wrist, ankle, and back was similar (28-37%) although 62% of lesions were on the legs. Recovery of a serotype from normal skin was associated with a high risk (76%) of subsequent development of lesions due to that type. New streptococcal serotypes usually entered a family during the peak or decline of a preceding serotoype with a tendency of one to predominate. Among family members the mean interval from index to secondary skin acquisition of streptococci was 4.8 days, but 21 days elapsed from first appearance to last acquisition of skin disease. In the population as a whole, streptococci were recovered in high frequency from normal skin before the increase in prevalence of lesions and also later in the fall when cutaneous infections were absent.
Bullous impetigo due to Staphylococcus aureus is one of the most common bacterial infections of man, and its generalized form, staphylococcal scalded skin syndrome (SSSS), is a frequent manifestation of staphylococcal epidemics in neonatal nurseries. Both diseases are mediated by exfoliative toxins (ETs), which show exquisite pathologic specificity in blistering only the superficial epidermis. We show that these toxins act as serine proteases with extremely focused molecular specificity to cleave mouse and human desmoglein 1 (Dsg1) once after glutamic acid residue 381 between extracellular domains 3 and 4. Mutation of the predicted catalytically active serine to alanine completely inhibits cleavage. The mutated ETs bind specifically to Dsg1 by immunofluorescence colocalization and by coimmunoprecipitation. Thus, ETs, through specific recognition and proteolytic cleavage of one structurally critical peptide bond in an adhesion molecule, cause its dysfunction and allow S. aureus to spread under the stratum corneum, the main barrier of the skin, explaining how, although they circulate through the entire body in SSSS, they cause pathology only in the superficial epidermis.
Lip lesions are a common presentation to the pediatrician's office. These lesions are often benign in children, without significant functional morbidity. However, owing to the prominent placement of lips and their role in communication, lip lesions can be alarming to patients as well as to their parents. For these reasons the pediatrician has an important role in recognizing, diagnosing, and treating the various types of labial dermatoses that commonly present to a pediatric practice. Four of the most common lip lesions a pediatrician will see are herpes simplex/recurrent herpes labialis, impetigo, mucoceles, and hemangiomas. This paper reviews the current literature on the diagnosis, treatment, and management of these 4 lesions.
The introduction of mupirocin ointment gives the pediatrician a reliable topical alternative to oral antibiotic therapy for group A streptococcal and staphylococcal impetigo. It is as effective as oral antibiotics and is associated with fewer adverse effects. In superficial skin infections that are not widespread, mupirocin ointment offers several advantages. It is highly active against the most frequent skin pathogens, even those resistant to other antibiotics, and the topical route of administration allows delivery of high drug concentrations to the site of infection.
We measured the sensitivity to antibacterials of Staphylococcus aureus isolated from impetigo lesions during one year (from July 1994 to July 1995). The largest number of strains was resistant to gentamicin, followed by erythromycin. Few methicillin-resistant S. aureus strains were isolated and few strains were resistant to more than one drug. We conclude that nadifloxacin and tosufloxacin are likely to be most effective against S. aureus, but fusidic acid is more suitable for the treatment of children.
Impetigo, a contagious superficial pyogenic infection of the skin, can be treated orally or topically. Nowadays oral erythromycin is the treatment of choice, although flucloxacillin is preferred in areas where the causative micro-organisms are resistant to erythromycin. Topical mupirocin ointment has shown itself to be as effective as oral therapy in many cases and is less likely to be associated with unwanted effects. The availability of 2 forms of therapy-oral and topical-means that treatment can be tailored according to the preferences of the patient. Consequently, drug therapy is more likely to be used appropriately. Arguments for and against the prescribing of each form of therapy are presented.
200 patients with primary impetigo were studied. Staphylococcus aureus was the only organism isolated in 72.5%, beta-hemolytic streptococci, group A, in 10%, and both pathogens in 15%. 17 of the 50 streptococcal isolates were typed serologically; 11 of these belonged to potentially nephritogenic types. A majority of these cases had identical strains in the nose and throat. Hence, the primary source of skin streptococcal in this study may be the nasopharynx. Uncomplicated cases were treated with topical antibiotics, and oral antibiotics were added in 22 cases with extensive lesions, fever or a concurrent throat infection. None of the 200 patients developed acute glomerulonephritis and urinary analyses were normal at follow-up after 3 weeks.
Bacterial skin infections are very common and trigger destruction of the skin integrity. Impetigo is a consequence of group A beta-hemolytic streptococcus or Staphylococcus aureus infection. The clinical presentation in general is very typical and empiric treatment is usually successful. In cases of close contacts such as between classmates, athletes, or soldiers, the prompt recognition and appropriate treatment of the infection may stop an epidemic. We report a group of six soldiers who shared the same military equipment (physical shields) during hand-to-hand combat training. All of the soldiers had skin lesions and two of them suffered from systemic symptoms. Group A beta-hemolytic streptococcus and S. aureus were cultured from the impetiginous lesions. All patients recovered after systemic and/or local antibiotic treatments. These cases emphasize the need for the maintenance of proper hygiene throughout the training program to prevent spread of the disease and the importance of rapid diagnosis by bacteriological identification.
The faucial carrying of Streptococcus pyogenes in patients presenting impetigo was determined as a risk factor for non-suppurative complications (acute glomerulonephritis). The fauces cultures of these patients revealed a S. pyogenes colonization of 65% and all the isolates were penicillin-sensitive. It was concluded that the high percent of faucial colonization made a systemic antimicrobial treatment necessary.
PFGE has been extensively used to obtain a reliable intra-species differentiation, although this technique has not been completely standardized. In this study, PFGE was applied to analyze in detail the patterns of 19 lesional S. aureus strains isolated from patients with impetigo, compared with 15 non-lesional strains isolated from nasal or pharyngeal swabs of the same patients. The strain DNA was extracted and processed as previously reported, using the strictest protocol to limit the variations between different analytical sets. To obtain maximum sensitivity and comparability, the electrophoresis patterns were analyzed by an automated and computerized reader (GelDoc1000). The DNA fragments (range 12-15 bands) obtained for each individual strain were then divided into 39 zones including from 1 to 4 bands for a total of at least 91 possible different gel positions. The positivity for each zone (and/or the positivity for the individual bands contained) was associated with the lesional/non-lesional origin and with the face localization of the strains.