Dermatologic Manifestations of Staphylococcal Scalded Skin Syndrome

Updated: Sep 28, 2016
  • Author: Paul Benson, MD; Chief Editor: Dirk M Elston, MD  more...
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Overview

Background

Staphylococcal scalded skin syndrome (SSSS) is a toxin-mediated type of exfoliative dermatitis. Toxin-mediated staphylococcal syndromes comprise a group of blistering skin diseases, ranging in severity from localized bullous impetigo to staphylococcal scalded skin syndrome, in which superficial blistering and exfoliation follow widespread painful erythema.

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Pathophysiology

Staphylococcal scalded skin syndrome (SSSS) is caused by toxigenic strains of Staphylococcus aureus, usually belonging to phage group 2 (types 3A, 3B, 3C, 55, or 71). Two exotoxins (ETs), epidermolytic toxin A (ET-A) and epidermolytic toxin B (ET-B), are responsible for the pathologic changes seen in staphylococcal scalded skin syndrome. [1] These toxins cause intraepidermal splitting through the granular layer by specific cleavage of desmoglein 1 (also the target protein in the autoimmune blistering dermatosis, pemphigus foliaceus ), a desmosomal cadherin protein that mediates cell-to-cell adhesion of keratinocytes in the granular layer. [2, 3, 4]

Specific targeting of desmoglein 1 by ETs allows S aureus to proliferate and spread beneath the barrier of the skin. Crystal structures and amino acid sequences indicate that these toxins act as serine proteases and cleave desmoglein 1 after glutamic acid residue 381 between extracellular domains 3 and 4. The ET-A and ET-B amino acid sequences are approximately 40% identical with each other.

Researchers have found an additional ET family member, ET-D, by screening the genomes of S aureus isolated from patients with skin infections. They demonstrated that ET-D specifically digested desmoglein 1. However, only ET-A and ET-B have been firmly linked to human staphylococcal scalded skin syndrome. The ET-D gene was detected mainly in isolates from patients with skin and soft-tissue infections, such as furuncles, abscesses and finger pulp infections. [5, 6]

It has been suggested that ET-B is more frequently isolated than ET-A in children with staphylococcal scalded skin syndrome. This link between ET-B and generalized staphylococcal scalded skin syndrome might be due to increased virulence of ET-B or to more abundant ET-B release. Because ET-A is chromosome borne and ET-B is plasmid borne, multiple copies of the ET-B gene could possibly lead to higher ET-B production. However, levels of ET-A and ET-B are quite similar in vitro. The link between ET-B and generalized staphylococcal scalded skin syndrome may be explained, at least in part, by lower levels of anti-ETB antibodies than anti-ETA antibodies in the general population.

An asymptomatic adult carrier introduces the causative bacteria into the nursery. Asymptomatic nasal carriage of S aureus occurs in 20-40% of healthy individuals, with the organism being isolated from the hands, the perineum, and the axillae in a smaller proportion of the general population.

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Epidemiology

Frequency

United States

Staphylococcal scalded skin syndrome most commonly occurs in infants and in young children, and it tends to occur in outbreaks in neonatal nurseries or in day care nurseries. [7, 8, 9] Large outbreaks of staphylococcal scalded skin syndrome in neonatal nurseries have been described, but the occurrence of staphylococcal scalded skin syndrome in adults as a nosocomial infection appears to be exceptional; epidemics have never been observed.

Epidemiologic data on strains of S aureus that produce ET are scarce. In a prospective clinical and bacteriologic study, 5.1% of 944 isolates of S aureus were identified as ET producers. Staphylococcal scalded skin syndrome in adults is an exceedingly rare disorder, with only 50 reported cases.

International

A retrospective study at the Lagos University Teaching Hospital in Nigeria over a 12-year period (January 1995 to December 2006) reviewed the presentation, etiology, and prognosis of nonburn epidermal loss. Only 2 (9%) of 19 patients had confirmed staphylococcal scalded skin syndrome. The first patient was an 18-day-old boy and the other was a 26-day-old girl admitted with a left lateral thigh abscess. Cultures in both cases yielded the growth of S aureus, which responded well to antibiotic treatment and dressings. [10]

In another retrospective study in England, hospital admissions were reviewed to identify trends in community-onset disease that were likely to be caused by pathogenic staphylococci. Hospital admission rates for staphylococcal septicemia, staphylococcal pneumonia, staphylococcal scalded skin syndrome, and impetigo increased greater than 5-fold from 1989 through 2004. Staphylococcal scalded skin syndrome was seen primarily in individuals older than 16 years. This reflects the real increases in pathogenic community-onset staphylococcal disease over the past 15 years. [11] An outbreak in a maternity unit in England from December 2012 to March 2013 reinforced the importance of the role of healthcare workers in the nosocomial transmission of the syndrome. [12]

Race

Black children are less prone to staphylococcal scalded skin syndrome than white children.

Sex

A male-to-female predominance exists (2:1 in sporadic cases, 4:1 in epidemics).

Age

The disease most commonly affects children younger than 5 years, particularly neonates. A decreased ability to achieve renal clearance of toxins and a lack of specific immunity (antibody) to the toxins make neonates the group at highest risk.

Older children and adults may also develop the disease. In such cases, renal insufficiency or immunodeficiency (eg, HIV infection, advanced stage of cancer) appears to explain the susceptibility to the syndrome. This happens because for the development of staphylococcal scalded skin syndrome, a massive production of toxins or deficiency in their elimination must be present. Adults who are affected range in age from 19-91 years, with one half of the cases occurring in adults older than 60 years. [13, 14, 15, 16]

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Prognosis

The prognosis of the disease is good in children, and the mortality rate is low if they are treated. In adult cases of staphylococcal scalded skin syndrome, the mortality rate is high despite appropriate antibiotic therapy.

Children generally do well and are not as ill as their dramatic eruptions might suggest. Staphylococcal scalded skin syndrome is usually associated with a trivial infective focus in the conjunctivae or the skin; however, severe infections, such as sepsis, do contribute to a low but appreciable fatality rate (<10%). [17] Morbidity in the occasional child who develops cellulitis, sepsis, and pneumonia can be significant. In children, the foci of staphylococcal infections are usually the nasopharynx or localized skin infections.

Adults with staphylococcal scalded skin syndrome often have blood cultures positive for toxigenic S aureus, and mortality rates can be high (40-63%). [17] The predisposing conditions are renal failure and immunocompromise. In older patients, underlying consumptive infectious diseases contribute to the high mortality rates. [18]

Staphylococcal scalded skin syndrome has been reported as a complication of septic arthritis after an elective right knee arthroscopy and lupus nephritis associated with chronic immunosuppressant therapy. [19]

A single report describes concurrent staphylococcal scalded skin syndrome and toxic shock syndrome (TSS), an acute life-threatening illness caused by TSS toxin also produced by S aureus, in a 43-year-old man associated with a abscess from previous dental work. This patient had normal renal function, but the amount of toxin produced from the abscess may have overwhelmed the kidneys' capacity to remove it. Although colonization with a strain of S aureus capable of producing TSS toxin and ET-Aor ET-B is possible, the clinical presentation of both staphylococcal scalded skin syndrome and TSS is extremely uncommon. [20] Only one other such case has been reported. [21]

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