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Staphylococcal Toxin-Mediated Scalded Skin and Toxic Shock Syndromes

Synonyms:

SS—Ritter's disease, Ritter von Rittershain's disease

TS—None

Etiology:

SS—Phage infected strains of S. aureus

TS—Non-phage toxigenic strains of S. aureus

Associations:

SS—Children with head/neck Staph infections; adults with

renal failure

TS—90% menstruating women, 10% skin/soft tissue

infection

Clinical:

SS—Red macular rash to generalized flaccid bullae

TS—Fever, hypotension and macular erythroderma

Histology:

SS—Subcorneal (intragranular layer) cell-poor blister with

acantholysis

TS—Neutrophilic pustular dermatitis with necrosis

IHC repertoire:

SS—Not applicable

TS—Not applicable

Staging:

SS—Not applicable

TS—Not applicable

Prognosis:

SS—Children 2-3% mortality; adults ~40%

TS—5%

Adverse signs:

SS—Bacteremia, renal failure

TS—Shock, encephalopathy and renal failure

Treatment:

SS—Oral/intravenous antibiotics

TS—Tampon removal, intravenous antibiotics/fluids

The toxin-mediated staphylococcal syndromes of staphylococcal scalded skin syndrome (SSSS) and toxic shock syndrome (TS) constitute important dermatologie entities capable of producing significant morbidity and mortality. Distinctive clinical and pathologic attributes usually permit their early recognition allowing for prompt institution of potentially life-saving therapy.

Credit for the first clinical description of SS belongs to Ritter von Rittershain, who in 1878 described 297 cases of a generalized exfoliative exanthem in neonates (1). An association with staphylococcus and subsequently the mechanism of phage-mediated toxin elaboration would be discovered in the 1940s and 1950s. Today, it is known that the epidermolytic toxins elaborated by viral phage-infected strains 71 and 55 of Staphylococcal aureus are responsible for the characteristic clinical and pathologic findings of this disorder. Interestingly, the target of the exfoliative toxin is pathogenically identical to superficial pemphigus (2,3). Both involve the disruption of the cad-herin adhesion molecule desmoglein 1 antigen, hence the pathologic similarity between these two otherwise distinctive disorders. The toxin is renally excreted, thus the epidemiologic association between the relatively decreased renal clearance mechanisms characteristic of young children and among the renally impaired adult (4-6). Unlike children, adults with SS are more likely to have positive blood cultures. SS has been described in conjunction with HIV disease in the adult (7).

The historical experience with TS is much more brief. The association of a multiorgan systemic toxic syndrome with certain strains of staphylococcus and menstruating women using superabsorbent tampons would emerge in the early 1980s (8). Although most of the initial reports involved menstruating women, it was subsequently determined that the syndrome could occur in accordance with soft tissue and cutaneous infections by toxin-producing strains of Staphylococcus aureus. Important risk factors for non-menstrual TS include minor abrasions that serve as a portal for toxin entry, burns, trauma, and antecedent surgery (9,10). Since the removal of superabsorbent tampons from the market, non-menstrual TS is now the most common presentation of this illness. A common clinical antecedent of non-menstrual TS is streptococcal necrotizing fasciitis. Following entry into the bloodstream, the toxins themselves, termed TSST-1 and enterotoxin C1, are non-phage related and produce illness on the basis of TNF-like properties including hypotension, fever, and leukocyte activation (11).

The clinical presentations of these entities are distinctive. SS is broadly grouped into three different forms termed generalized, localized, and abortive disease (12). Generalized SS is the most important manifestation of the disease and is ascribed the greatest risk for complications. This form is associated with remote staphylococcal infection of the head and neck area including conjunctivitis or otitis media. The symptoms are heralded by the development of an orange-red, often tender macular rash. The rash may show periorificial or flexural accentuation. Within 24 to 48 hours, flaccid bullae typically develop. The blister roof is typically wrinkled and expands, forming large cavities, in particular involving flexural sites such as the groin or axillae. The blisters are typically Nikolsky's sign-positive and when removed, yield an erythematous glistening base. Despite widespread involvement of the bodily surfaces, the mucous membranes are characteristically spared. This stage is typically followed by desquamation and complete resolution within 5 to 7 days. Clinical improvement coincides with the presence of neutralizing serum antibodies to the toxin. The localized form of disease is synonymous with bullous impetigo and represents localized infection by toxigenic strains of S. aureus. As with the generalized form, this entity is typically encountered in children. The lesions are represented by superficial erosions with minimal gray exudates or by fragile vesicles or bullae filled with turbid fluid and surrounded by an erythematous rim. Lesions are typically encountered on the exposed surfaces of the skin and in particular, periorificial sites. Unlike the generalized form of the disease, wound cultures and Gram stains are positive for staphylococcus. The abortive form of the disease is less common and essentially consists of regionally limited bullae, the dermatologic manifestations of which may be confused with TS.

The clinical presentation of TS is ushered in by the precipitous development of high fever, hypotension, and

Figure 28.1. Epidermal loss with erythematous base seen in toxie shock syndrome.

macular rash (9). The rash is often localized to the site of infection and typically shows pronounced erythema with associated non-pitting edema (Figure 28.1). The conjunctivae are often injected and the oral mucosa may show petechiae and diffuse erythema. The rash is often followed by desquamation, in particular involving the palms and soles. Important systemic accompaniments to the rash to be cognizant of include painful skeletal muscles associated with rhabdomyolysis, decreased urine flow/hematuria associated with the azotemia and enceph-alopathy of renal failure, jaundice with hepatitis and hemorrhage associated with thrombocytopenia and disseminated intravascular coagulation. A related condition consisting of recurring erythematous rash and desquamation has been described in HIV patients, termed recalcitrant erythematous desquamating disorder, that produces a subacute illness of longer duration and high mortality (13).

Important considerations within the diagnostic differential of these entities include Kawasaki's disease, drug eruption, scarlet fever, and toxic epidermal necrolysis (TEN). Kawasaki's disease shows many of the features of TS, similarly sharing fever, conjunctivitis, and desquamative rash that can, however, usually be distinguished on the basis of the patient's age (Kawasaki's, 90% less than 5 years), lack of hypotension, and the presence of lymphadenopathy. Drug eruption and scarlet fever are seldom associated with hypotension. TEN is typically seen in adults and usually follows ingestion of an offending medication. Unlike TS, hypotension is not commonly seen in the early stages of TEN.

The histopathology of these entities is distinctive. SS shows blister formation situated within the epithelium just below the stratum corneum or within the granular layer (14) (Figures 28.2 and 28.3). The blister cavity typi-

Figure 28.2. Low power photomicrograph of SSSS. Note subcorneal blister formation.

cally contains free-floating keratinocytes (acantholysis) and is devoid of inflammatory cells. Special (gram) stain for bacteria is negative. The dermis may show a sparse superficial perivascular lymphocytic or neutrophilic infiltrate. Localized forms of SS (bullous impetigo) show, in addition to the blister, copious numbers of neutrophils and pyogenic organisms. The histologic findings of TS show pustular collections of intraepithelial and subcor-neal neutrophils with single and grouped dyskeratotic and necrotic keratinocytes. The dermis often shows edema with a perivascular and interstitial infiltrate of neutro-phils and lymphocytes.

The therapy for SS should be directed toward treatment of the underlying infection. As most infections are produced by methicillin-resistant Staphylococcus aureus, appropriate intravenous penicillinase-resistant antibiotics are indicated. Attention to fluid and electrolyte balance and local wound care precautions are important. Compli cations include cellulitis, osteomyelitis, pneumonia, and, in the adult, sepsis. Measures that prevent the nosocomial transmission of the organism, including patient isolation, health provider handwashing, barrier functions, and oral antibiotic therapy for infected health care providers, should be considered.

The overall mortality rate of SS in children is about 3%, increasing to 40%-50% among immunosuppressed or renally impaired adults. The management of TS involves rapid intravenous resuscitation to ameliorate hypotension, removal of infected tampon or identification of the underlying infection, and appropriate intravenous anti -biotics (15). Antimicrobial therapy generally consists of cell-wall active agents (i.e., penicillin) with adjunctive clindamycin. Intravenous gamma globulin and/or immunoglobulin containing fresh frozen plasma has also shown promise in therapy. The overall mortality of TS is approximately 5%.

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Figure 28.3. High power detail of subcorneal blister with scattered neutrophils. Note the absence of acantholysis.

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