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.

Extremely low levels of epidermal skin-derived antileucoproteinase/elafin in a patient with impetigo herpetiformis.

Impetigo herpetiformis (IH) is a rare pustular dermatosis with unknown aetiology, typically occurring during pregnancy. Based upon a similar clinical and histological presentation, i.e. spongiform accumulation of polymorphonuclear leucocytes in the stratum corneum, several authors consider IH as a variant of generalized pustular psoriasis (GPP), while others state that IH is a separate entity. Skin-derived antileucoproteinase (SKALP) is a strong and specific inhibitor of human leucocyte elastase (HLE) and proteinase 3, two neutral proteinases that have been implicated in leucocyte migration and tissue destruction. Previously, we reported decreased SKALP activity in pustular forms of psoriasis compared with plaque psoriasis. In this study we present a case study of a patient with IH, where SKALP activity was measured using biochemical and immunochemical techniques. Epidermal scales and sera were collected during the course of the disease. Comparison was made with three patients with GPP and six patients with plaque psoriasis. Initially, anti-HLE activity in epidermal scales of the patient with IH was comparable with values in patients with GPP, i.e. decreased compared with plaque psoriasis. During the course of the disease, anti-elastase activity dropped to undetectable levels, concomitant with the appearance of free elastase activity. This finding suggests a total saturation of epidermal anti-HLE activity. Low levels of SKALP, presumably complexed with HLE, could be measured immunochemically in scale extracts. Serum levels of total SKALP correlated with the disease activity. We suggest that a reduced amount of epidermal SKALP contributes to an imbalance between elastase and its inhibitor, resulting in the formation of epidermal pustules. This mechanism of pustule formation could apply both to GPP and IH, suggesting a final common pathway in the pathogenic mechanisms of IH and GPP.

Staphylococcal scalded skin syndrome. II. Serum level of anti exfoliatin and anti alpha-toxin in patients with staphylococcal scalded skin syndrome or bullous impetigo.

In order to study the differences between staphylococcal scalded skin syndrome (SSSS) and bullous impetigo, the anti exfoliatin level was assessed in the sera from both groups of patients, and no significant difference in the level was found. However a significant difference was noted in the anti alpha-toxin levels in sera from both group of patients; that of SSSS patients was much lower than that of impetigo patients and of children in a control group. Five out of 6 patients with SSSS showed an unchaged level of anti alpha-toxin at the second examination, while an increased anti exfoliatin level was noted in 4 out of 6 SSSS patients.

Experimental infection of the skin in the hamster simulating human impetigo. IV. Cellular responses after streptococcal and staphylococcal infections.

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.

Complement in overt and asymptomatic nephritis after skin infection.

In an ongoing study of streptococcal skin infection and acute glomerulonephritis (AGN) begun in 1964, C'3 determinations were done in 784 patients. There were 126 patients with acute poststreptococcal nephritis, 172 of their siblings, and 486 patients with uncomplicated impetigo from families without an index case of nephritis.90% of the patients with nephritis were infected with one of the four prevalent streptococcal serotypes associated with nephritis in this population; only 12% of patients with uncomplicated impetigo were infected with similar serotypes.93% of the patients with overt nephritis had diminished complement levels. Low complement was more often observed (8%) in AGN siblings than was transient hypertension and/or hematuria (5%). Considering the relationship of low C'3 alone and low C'3 preceded hematuria in four others. Two (0.4%) of the patients with uncomplicated impetigo had low complement values, both of whom were infected with nephritogenic strains. Transient hematuria and/or hypertension was less frequently observed (2.7%) among patients with uncomplicated impetigo. Serial determinations in patients with low complement revealed a return to normal in a linear fashion within 2-12 wk. The validity of the hypothesis that the asymptomatic patients with low complement levels, with or without hematuria, likely had subclinical nephritis is strengthened by the accompanying epidemiologic data. The finding of low complement before the onset of, or in the absence of, hematuria or other evidence of nephritis supports the concept that an immunologic mechanism may precipitate the renal injury of acute streptococcal nephritis.