CELLULITIS acute, subacute, or, on rare occasions, cbronic. Trauma, or breaks in the protective cutaneous skin layer,

signs and symptoms pain or tenderness, erythema that blanches on palpation, swelling of the involved area, and local warmth.

Risk factors for cellulitis include lymphedema, a portal of entry, venous insufficiency, and obesity. Interestingly, diabetes mellitus, alcohol misuse, and smoking are not associated with increased

cellulitis

Differential Considerations, including arthropod and marine envenomation, the inflammatory response to foreign bodies, healing or postsurgical wounds, chemical or thermal burns, septic or inflammatory joints, dermatitis, and the arthritides.

Fever Fever is uncommon and should prompt the physician to consider secondary bacteremia or systemic involvement.

WBC white blood cell counts are usually normal or mildly elevated with little or no shift to theleft. One exception is H. influenzae B in children.

H. influenzae B This cellulitis is usually associated with high fever and white blood cell counts greater than 15,OOO/mm', with a left shiFT

Diagnostic Strategies A recent study of needle aspiration of cellulitis indicated that only about 10% of the time is the causative bacteria identified.'

Diagnostic Strategies Blood cultures of patients with cellulitis are also not helpful, except in cases of H. influenzae B cellulitis, which are associated with bacteremia in children more than two thirds of the time. "8

Soft tissue radiographs and ultrasonograms may be useful to detect radiopaque foreign bodies, including glass. Computed tomography or magnetic resonance imaging scans are reserved for instances in which deep space infections or abscesses are suspected. For most l ocalized infections, no radiographic procedures are INDICATED

Management immobilization, elevation, heat or warm moist packs, analgesics, and antibiotics.

Periorbital (Preseptal) and Orbital Cellulitis must be treated aggressively. The venous drainage of that area is through communicating vessels into the brain via the cavernous sinus. Streptococcal species are currently the most common infecting organisms.

Streptococcal Cellulitis Streptococcal cellulitis, often termed ascending cellulitis, is usually seen after surgery or trauma but can occur with no predisposing event.

Ascending cellulitis Ascending cellulitis usually progresses rapidly with prominent Iymphangitic streaking and a swollen extremity. Untreated patients can quickly become toxic.

Erysipelas acute superficial cellulitis characterized by a sharply demarcated border surrounding skin that is raised, deeply erythematous, indurated, and painful.

CONT Patients usually appear toxic, with a prodrome of fever, chills, and malaise preceding the eruption of a bright red cellulitis predominantly on the lower extremities

ANTIBIOTIC Penicillin G continues to be a standard treatment, but amoxicillin can also be used for 10 to 20 days. Macrolides, cephalosporins, and fluoroquinolones have been shown to be more effective but should be reserved for complicated cases."

Staphylococcal Cellulitis Staphylococcus aureus produces various toxins that result in local and s Tissue invasion, blister formation, and inflammation are caused by toxins such as alpha toxin, hyaluronidase, fibrinolysin, ystemic effects

Staphylococcal Scalded Skin Syndrome caused by an exfoliative toxin produced by phage group II, type 71 staphylococci. The syndrome usually occurs in children between the ages of 6 months and 6 years

Staphylococcal Scalded Skin Syndrome Mucous membranes are usually not involved. Nikolsky's sign, the easy separation of the outer portion of the epidermis from the basal layer when pressure is exerted. is often present.

Staphylococcal Scalded Skin Syndrome characterized by the formation of bullae and vesicles leading to the loss of large sheets of superficial epidermis.

Diagnostic Strategies clinical pattern of tenderness, erythema, desquamation, or bullae formation; (2) histopathologic evidence of intraepidermal cleavage through the stratum granulosum; (3) isolation of an exfoliative exotoxin producing S. aureus, and (4) the absence of pemphigus foliaceus by immunofluorescence

Management includes adequate hydration, management of fluid and electrolyte balance, and treatment with systemic antibiotics such as a penicillinase-resistant penicillin.'6

Haemophilus influenzae Cellulitis. The patient appears acutely ill, often with a high fever, a white blood cell count greater than 15,000, and a high incidence (75-90%) of positive blood cultures. With widespread H. influenzae B immunization, there has been a dramatic decrease in the incidence of H. influenzae skin infections

Management Treatment is parenteral antibiotics with a second- or third-generation cephalosporin followed by ampicillin/ clavulanic acid for a total of 10 to 14 days

Gram-Negative and Anaerobic Cellulitis immunocompromised patient. Cellulitis is seen most often around mucous membranes. primarily the perineum and in chronic wounds that are not kept clean and thus become superinfected.

TOXIC SHOCK SYNDROME often occurs in menstruating women who use vaginal tampons.

Diagnostic Strategies A creatinine level greater than 2.5 mg/dL indicates renal involvement, which may precede hypotension. Serum creatine kinase correlates well with deep soft tissue involvement, and increasing values may indicate necrotizing fasciitis or myositis ("flesh-eating bacteria").

CONT hypoalbuminema, hypocalcemia, and a sometimes mild leukocytosis with prominent "left shift."

CONT disseminated intravascular coagulation. Blood cultures are positive 60% of the time, and wound cultures are positive in 95% of cases.

CONT penicillin plus clindamycin, erythromycin, or ceftriaxone plus clindamycin.

IMPETIGO Impetigo is a superficial infection of the skin caused by group A ~-hemolytic Streptococcus and occasionally coagulase-positive S. aureus.

CELLULITIS

NECROTIZING FASCIITIS

MYONECROSIS

Admission Criteria Toxic appearing Tissue necrosis History of immune suppression Concurrent chronic medical illnesses Unable to take oral medications Unreliable patient

Discharge Criteria Mild infection in a non-toxic-appearing patient Able to take oral antibiotics No history of immune suppression or concurrent medical problems No hand or face involvement Has adequate follow-up within 24 to 48 hours

ADMISSION ROSEN febrile patient severe infections involving significant portions of an extremity (particularly the hands and feet), the head and neck, or the perineum. Inpatient management is also often required for adequate treatment of significant cellulitis of the lower limb and hand.

continues to worsen after 48 to 72 hours All patients with cellulitis must be monitored closely to ensure that the process is resolving. immunocompromise, diabetic, alcoholic, on chemotherapy or steroid therapy,

asplenic, or at extremes of age require aggressive monitoring and treatment. hypotension, confusion, crepitus, or bullae formation of the involved soft tissues.

END