The Skin and Beyond:Skin and Soft Tissue Infections

John Sinnott, MD, FACPAssociate Dean, International Affairs

Director, Signature Program in Allergy, Immunology and Infectious DiseaseDirector, Division of Infectious Disease

University of South Florida, College of Medicine

Pretentious Quote:

… [T]he skin has diseases, one of those diseases is man.

Friedrich Nietzsche

In General: Skin Lesions

Tumors Rashes

Melanoma:

• A symmetric

• B order — irregular

• C olor — pigment variable

• D iameter > 0.5 cm

Skin Infections:

LAYER INFECTION

Epidermis Impetigo

Dermis Erysipelas

SubQ Cellulitis

Fascia Fasciitis-(NSTI)

Muscle Myositis-(NSTI)

Pathogens:

• Impetigo contagiosum – GAS

• Impetigo bullosum – Staph

• Erysipelas – GAS

• Cellulitis – Staph, GAS

• Fasciitis – GAS, Mixed

• Myositis – Clostridia

CA-MRSA: NB

• CA – MRSA is increasing and may become more like HA-MRSA

DM, prisoners, contact sports are old risk groups; now everyone is at risk

Variant Cellulitis: Bites or Water !

Human Bite: GAS

anaerobes

Dog Bite: C. canimorsus

P. multocida

Cat Bite: P. multocida

Saltwater: V. vulnificusM. marinum

Fresh water: E. tarda

A. hydrophila

Edwardsiella: Treatment

• All Edwardsiella sensitive to: – Tetracyclines, aminoglycosides, most

B-Lactams, cephalosporins, quinolones, antifolates

• All Edwardsiella resistant to:– Macrolides, streptogramins, glycopeptides,

rifampin, PRSP’s

Stock I, Wiedemann B. Natural Antibiotic Susceptibilities of Edwardsiella tarda, E. ictaluri, and E. hoshinae. Antimicrob Agents Chemother, 2001 August; 45 (8): 2245-2255.Harrison's Principles of Internal Medicine, 16th Edition. Kasper D, Braunwald E, Fauci A, et al, Eds. 134: 6. 2006

Necrotizing Soft Tissue Infections: “NSTI’S”

• Fournier’s gangrene

• Clostridial anaerobic cellulitis

• Clostridial gas gangrene

• Necrotizing fasciitis– Type 1 NF- polymicrobial (Fournier’s)

– Type 2 NF- Grp A Strep (IVIG, HB O2)

Gas in Soft Tissue:

• Non-bacterial Causes– Trauma / Surgery

– Air Injection

– H2O2 Irrigation

• Bacterial– Glucose Fermenting

Diagnosis NSTI’s:

• Serial exams!

• Serial exams!

• Soft tissue X- ray, MRI, CT

• Low threshold for surgery–Full thickness frozen-section Bx–Direct visualization–Gram stain

Management and Therapy:

• Hemodynamic stabilization, nutrition, lytes, fluid resuscitation, oxygenation

• Early, aggressive and repetitive debridement

• Early, aggressive and repetitive debridement

• Hyperbaric tx• A-B’s

37 y/o male with alcoholic cirrhosis admitted for RLE cellulitis; DX necrotizing fasciitis, BCX grew Group Strep A

37 y/o male with alcoholic cirrhosis admitted for RLE cellulitis; DX necrotizing fasciitis, BCX grew Group Strep A

37 y/o male with alcoholic cirrhosis admitted for RLE cellulitis; DX necrotizing fasciitis, BCX grew Group Strep A

Miscellaneous Dermatologic Manifestations of Disease:

• Pseudomonas folliculitis• Herpetic Whitlow• Herpes Gladiatorum• Molluscum Contagium• Seborrheic Dermatitis• Secondary Syphilis

“We know too much and believe too little.”

T. S. Elliot

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