Erysipelas

Definitions of Skin/Soft Tissue Infections

  • Cellulitis (see Cellulitis, [[Cellulitis]]): skin infection of deeper dermis and subcutaneous fat (resulting from bacterial breach of the skin) characterized by erythema, warmth, and edema without an underlying suppurative focus
  • Erysipelas: skin infection of upper dermis and superficial lymphatics (resulting from bacterial breach of the skin) characterized by erythema, warmth, and edema without an underlying suppurative focus
  • Impetigo (see Impetigo, [[Impetigo]]): infection of superficial layers of the epidermis
  • Necrotizing Soft Tissue Infection (see Necrotizing Soft Tissue Infection, [[Necrotizing Soft Tissue Infection]]): all of these are characterized by fulminant tissue destruction, systemic toxicity, and high mortality rates
    • Necrotizing Cellulitis
      • Meleney’s Synergistic Gangrene
      • Clostridial Anaerobic Necrotizing Cellulitis
      • Non-Clostridial Anaerobic Necrotizing Cellulitis
    • Necrotizing Fasciitis: deep-seated infection of subcutaneous tissue (involving fascia and fat), which may spare the skin
      • Type I (Mixed Aerobic and Anaerobic Infection)
      • Type II (Monomicrobial Infection)
    • Necrotizing Myositis (Spontaneous Gangrenous Myositis)
  • Clostridial Myonecrosis (Gas Gangrene) (see Clostridial Myonecrosis, [[Clostridial Myonecrosis]]): life-threatening muscle infection which develops either contiguously from a site of trauma or via hematogenous spread from the gastrointestinal tract to the muscle
  • Furuncle (Boil) (see Skin Abscess, [[Skin Abscess]]): infection of hair follicle where purulent material extends through the dermis into the subcutaneous tissue, forming a small abscess
  • Carbuncle (see Skin Abscess, [[Skin Abscess]]): coalescence of several inflamed follicles into a single inflammatory mass with purulent drainage from multiple follicles
  • Skin Abscess (see Skin Abscess, [[Skin Abscess]]): collection of pus within dermis and deeper skin tissues

Predisposing Factors

Local Factors

  • Skin Barrier Disruption: penetrating wound, IV drug abuse, etc
  • Skin Inflammation: eczema, radiation therapy, etc
  • Pre-Existing Skin Infection: impetigo, tinea pedis, etc
  • Edema: venous insufficiency, etc

Systemic Disease


Microbiology

  • Staphylococcus Aureus (see Staphylococcus Aureus, [[Staphylococcus Aureus]])
  • Streptococcus Pyogenes (Group A Strep) (see Streptococcus Pyogenes, [[Streptococcus Pyogenes]]): most common etiology of erysipelas
  • Other Streptococcus (see Streptococcus, [[Streptococcus]])
  • Gram Negative Organisms

Diagnosis

Complete Blood Count (CBC) (see Complete Blood Count, [[Complete Blood Count]])

Blood Culture (see Blood Culture, [[Blood Culture]])

  • Sensitivity/Specificity: positive in <5% of cases
  • Indications for Blood Cultures
    • Extensive Skin Involvement
    • Recurrent/Persistent Infection
    • Specific Exposures
    • Specific Host Factors
      • Asplenia/Splenectomy (see Asplenia, [[Asplenia]])
      • Diabetes Mellitus (see Diabetes Mellitus, [[Diabetes Mellitus]])
      • Immunosuppression/Immunodeficiency
      • Lymphedema
      • Malignancy
      • Neutropenia (see Neutropenia, [[Neutropenia]])
    • Systemic Toxicity

Culture of Pus

  • Sensitivity/Specificity
    • Cultures of swabs from intact skin are rarely useful
    • Cultures of swabs from toe web intertrigo due to tinea pedis may be useful to identify pathogenic organisms in lower extremity cellulitis
  • Indications for Cultures of Pus
    • Extensive Skin Involvement
    • Recurrent/Persistent Infection
    • Specific Exposures
    • Specific Host Factors
      • Asplenia/Splenectomy (see Asplenia, [[Asplenia]])
      • Diabetes Mellitus (see Diabetes Mellitus, [[Diabetes Mellitus]])
      • Immunosuppression/Immunodeficiency
      • Lymphedema
      • Malignancy
      • Neutropenia (see Neutropenia, [[Neutropenia]])
    • Systemic Toxicity

Skin Punch Biopsy

  • Sensitivity/Specificity: only positive in 20-30% of cases
    • Suggests that relatively small numbers of bacteria may result in significant inflammation with most of the observed findings being due to the host inflammatory response
    • Usually not performed

Needle Aspiration of Bullae

  • Sensitivity/Specificity: positive in <5-40% of cases
    • Suggests that relatively small numbers of bacteria may result in significant inflammation with most of the observed findings being due to the host inflammatory response
  • Indications for Needle Aspiration of Bullae
    • Extensive Skin Involvement
    • Recurrent/Persistent Infection
    • Specific Exposures: animal bite, water-associated injury
    • Specific Host Factors: lymphedema, malignancy, neutropenia, immunosuppression/immunodeficiency, splenectomy, diabetes
    • Systemic Toxicity

X-Ray/CT/MRI

  • May be useful in some cases to exclude skin abscess or to distinguish cellulitis/erysipelas from osteomyelitis or gas gangrene
    • However, radiologic exams cannot reliably differentiate cellulitis from necrotizing fasciitis or gas gangrene and these should not delay surgical intervention if necrotizing fasciitis or gas gangrene are suspected

Clinical Manifestations

Dermatologic Manifestations

  • Skin Erythema, Warmth, and Edema without an Underlying Suppurative Focus, with Lesions That are Characteristically Raised Above the Level of the Surrounding Skin: with clear line of demarcation between involved and uninvolved skin
    • Most Common Site of Involvement: lower extremities
    • Pain: may occur
    • Associated Lesions: variably occur
      • Vesicles/Bullae (see Vesicular-Bullous Skin Lesions, [[Vesicular-Bullous Skin Lesions]])
      • Ecchymoses
      • Petechiae (see Petechiae, [[Petechiae]])
      • “Peau D’Orange” (Orange Peel) Appearance: due to edema surrounding hair follicles with dimpling of the skin

Other Manifestations

  • Lymphangitis/Inflammation of Regional Lymph Nodes (see Lymphadenopathy, [[Lymphadenopathy]]): may occur
  • Sepsis (see Sepsis, [[Sepsis]])

Treatment

  • xxx

References

  • Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59(2):e10-52. doi: 10.1093/cid/ciu444 [MEDLINE]