November 2014 Dermatology Clinic
A black male infant, aged 3 months, presents to the emergency room with a rash and fever. His mother reports that the patient first developed periorbital swelling and facial edema 5 days before presentation; 3 days before, he developed a fever followed by a desquamating rash that began on the neck, spreading to the arms, back, legs, and perirectal area.
The infant is otherwise healthy and on no medications; he had not been in contact with people who were ill. The physical exam is notable for generalized erythema and superficial desquamation of the face, neck, axillae, back, upper chest, and perirectal area with perioral linear radial fissuring.
This The Clinical Advisor CME activity consists of 3 articles.To obtain credit, read Itchy, tense blisters and acne-like rash around the nose and mouth. Then take the post-test here.
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Staphylococcal scalded skin syndrome (SSSS) is a bacterial infection of specific staphylococcal strains with the ability to produce exfoliative (also known as epidermolytic) toxins.1 SSSS is also known as Ritter disease, pemphigus neonatorum, and dermatitis exfoliative neonatorum.1,2
The condition is most often seen in infants and young children.1 The exfoliative toxin produced by these staphylococcal strains are renally excreted.1 It is hypothesized that infants (especially neonates) and young children are more predisposed to this disease due to decreased renal toxin clearance and/or a lack of antibodies that neutralize exfoliative toxins.
Because decreased renal clearance and lack of antibodies are thought to increase the risk of SSSS, it is not surprising that SSSS may also be seen in adults with chronic renal insufficiency, immunosuppression, malignancy, heart disease, or diabetes.1,3
Outbreaks of SSSS have been reported in neonatal nurseries, usually secondary to asymptomatic carriage of a toxigenic strain of S. aureus by health-care workers or other patients.1 For unclear reasons, males are disproportionately affected, with a male-to-female ratio of 2 to 1 in sporadic cases and 4 to 1 in epidemics.1
SSSS is usually caused by strains of S. aureus in phage group II (e.g., types 55, 71).1 The pathogenesis of SSSS arises from the production of exfoliative toxins by these strains of S. aureus. Exfoliative toxins are classified as ETA or ETB, depending on the location of their genetic material: ETA is chromosomally encoded, whereas ETB is plasmid-encoded.1,3
These toxins are serine proteases that cleave desmoglein 1 (Dsg1), a cell-to-cell adhesion molecule found in desmosomes in the upper layers of the epidermis.1 Thus, when these toxins bind Dsg1, a disruption occurs in the upper epidermis, leading to the formation of superficial bulla.1 Typically, there is a focus of S. aureus infection with hematogenous spread of the exfoliative toxins. In children, the foci of infection is usually in the nasopharynx or conjunctiva, whereas in adults, the source of infection is usually staphylococcal pneumonia or bacteremia.1
Other reported sources of infection include septic arthritis, endocarditis, and pyomyositis.3 Bullous impetigo is a localized form of SSSS.1 Dsg1 is the same target of antibody production in pemphigus foliaceus, another blistering disorder of the superficial epidermis.3 Pathogenic staphylococcal strains can be sensitive or resistant to methicillin.1
The severity of SSSS may range from mild, localized disease to widespread exfoliation.3 SSSS generally begins with a localized infection, often of the conjunctivae, nares, perioral region, perineum, or umbilicus.3 With production of exfoliative toxins from this foci of infection and hematogenous dissemination, patients with SSSS often present with a prodrome of malaise, fever, irritability, and pronounced skin tenderness.1 Poor feeding is also commonly noted.3
This is often followed by erythema that begins on the head and fold areas with generalization within 48 hours.1 Facial edema is sometimes noted. The skin then develops a wrinkled appearance due to the formation of superficial bullae.1
There is often a positive Nikolsky sign (progression of a blister by pressure on the edge of a bulla).1 When the superficial bullae rupture, exfoliation is noted, leaving behind moist skin and thin, varnish-like crusting.1 The intertriginous areas are usually the first to exfoliate. Patients often develop periorificial crusting and radial fissuring, leading to the description of “sad man” facies.1
Because of the relative paucity of Dsg1 in the oral mucosa, intraoral lesions typically do not occur.1 Scaling and desquamation usually continue for 3 to 5 days.1 Due to the superficial nature of the bullae, the affected areas heal without scarring.1 Typically, SSSS resolves in 1 to 2 weeks, usually with no long-term complications.1 However, when there is extensive denudation of skin, patients may have a greater loss of heat, fluids, and electrolytes with increased risk for secondary infection and possibly sepsis.3
The mortality rate is 3% in children.1 In adults, the mortality rate can be greater than 50%, because SSSS develops in this population with premorbid conditions such as renal disease and immunosuppression.1
The diagnosis of SSSS is often made on clinical grounds. Of note, because bullae are formed from exfoliative toxins that have spread hematogenously from a distant foci of infection, culture of the bullae will be negative.1 If such a study is still desired, the conjunctiva, nasopharynx, feces, or pyogenic foci should be swabbed and cultured.1
A skin biopsy is usually unnecessary; however, if performed, histopathology is notable for a split at or below the stratum granulosum in the upper epidermis.1 There are usually no inflammatory cells in the bullae. No organisms are seen on Gram stain of biopsy specimens.1
The leukocyte count is variably elevated or normal.1 Although toxins may be detected with slide latex agglutination, double immunodiffusion, or enzyme-linked immunosorbent assay (ELISA), these tests are not often performed.1
There is rarely a differential diagnosis because of the characteristic findings of SSSS. However, the most important distinction is from toxic epidermal necrolysis (TEN) or Stevens-Johnson syndrome (SJS), which are life-threatening dermatologic conditions.
The most important distinction is that TEN and SJS present with full-thickness necrosis of the skin, whereas SSSS creates superficial bullae. SJS, by definition, affects mucosal surfaces and most characteristically presents with thick heme crust on the lips. SSSS, on the other hand, typically spares the oral mucosa. In addition, it should be noted that bullous impetigo is a localized form of SSSS.
Antibiotics are the mainstay of therapy. For mild disease, treatment with a beta-lactamase-resistant antibiotic, such as cephalexin, for 7 to 10 days is usually sufficient.1 However, patients with severe, generalized SSSS are often treated with parenteral antibiotics.1
Most commonly, intravenous clindamycin is administered, as clindamycin inhibits the production of ribosomal ribonucleic acid and thus theoretically inhibits protein production of exfoliative toxins in addition to addressing the S. aureus infection. Hospitalized patients should be placed on contact isolation.3 Patients with extensive disease require rigorous monitoring of fluids, electrolytes, pain management, and wound care.3
Our patient had mild skin involvement. He was admitted to the hospital and received intravenous clindamycin. After 3 days, he was discharged with no complications or sequelae and placed on a 10-day course of oral clindamycin.
Audrey Chan, MD, is a pediatric dermatology fellow at Texas Children’s Hospital in Houston.
This The Clinical Advisor CME activity consists of 3 articles.To obtain credit, read itchy, tense blisters and acne-like rash around the nose and mouth. Then take the post-test here.
- Bolognia JL, Jorizzo JL, Rapini RP, eds. Dermatology. 3rd ed. St. Louis, Mo.: Mosby Elsevier; 2011: Chap. 74.
- James WD, Berger T, Elston D. Andrews’ Diseases of the Skin. 11th ed. Philadelphia, Pa.: Elsevier; 2011:252.
- Paller AS, Mancini AJ. Hurwitz Clinical Pediatric Dermatology. 4th ed. Philadelphia, Pa.: Elsevier Saunders; 2011: 331-333.