Cellulitis Clinical Presentation

Updated: Apr 26, 2022
  • Author: Thomas E Herchline, MD; Chief Editor: Michael Stuart Bronze, MD  more...
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A directed history is vital to the proper care of a patient with cellulitis. The patient may or may not relate an episode of trauma that preceded symptoms; when cellulitis develops, it is usually several days after the inciting trauma. Rapid progression or significant pain is a concerning sign that may indicate a severe problem, such as necrotizing fasciitis, which should be managed promptly. [1]

If the patient recalls an episode of trauma, the clinician should ask about circumstances surrounding the incident that may elicit clues to a particular etiology. For example, exposure to standing or brackish water could mean that Aeromonas or Vibrio is the cause of infection; or a cut that occurred while butchering may be an important clue to consider Erysipelothrix rhusiopathiae. Identifying the specific inciting cause helps the clinician identify the most likely pathogen, choose appropriate antibiotic therapy, and offer appropriate immunization, such as tetanus toxoid (Td or Tdap), if indicated. [1]

The patient should also be questioned about the presence of other skin disorders, including various types of dermatitis and especially any preceding fungal infection, which may serve as a portal of entry for bacterial pathogens. [21]

The past medical history should focus on the presence of comorbid conditions that may increase the risk for cellulitis, with the most common ones being diabetes mellitus, human immunodeficiency virus (HIV) infection/acquired immunodeficiency syndrome (AIDS), chronic kidney disease, and chronic liver disease. [1]

The surgical history may include a recent procedure that resulted in wound infection. For example, severe bacterial cellulitis may occur as a postsurgical complication following hip replacement [60] or liposuction. Alternatively, a remote surgical history involving lymph node dissection (eg, following either radical mastectomy or conservative breast surgery) may predispose to cellulitis, even years after the surgery, because of lymphatic occlusion. [61, 62, 63, 64] Impaired lymphatic drainage and edema are also considered predisposing factors to leg cellulitis following saphenous vein resection for coronary artery bypass. [26] In addition, the presence of foreign bodies, including indwelling IV catheters, external orthopedic pins, and other surgical devices, may predispose to infection. [1]


Physical Examination

The physical examination should first focus on the area of concern. Nonpurulent cellulitis is associated with four cardinal signs of infection: erythema, pain, swelling, and warmth. Several physical examination findings may help the clinician identify the most likely pathogen and assess the severity of the infection, thereby facilitating appropriate treatment. Those findings include the following [1] :

  • The involved site(s)is/are red, hot, swollen, and tender

  • Unlike erysipelas, the borders are not elevated or sharply demarcated

  • The involved site is the leg, which is the most common site [50, 65]

  • Regional lymphadenopathy is present

  • Malaise, chills, fever, and toxicity are present

  • Skin infection without underlying drainage, penetrating trauma, eschar, or abscess is most likely caused by streptococci; on the other hand, S aureus, often community-acquired methicillin-resistant S aureus (CA-MRSA), is the most likely pathogen when these factors are present [3]

  • Perianal cellulitis is usually observed in children with perianal fissures; it is characterized by perianal erythema and pruritus, purulent secretions, painful defecation, and blood in the stools [66]

  • Cellulitis characterized by violaceous color and bullae suggests more serious or systemic infection with organisms such as V vulnificus or S pneumoniae

    Cellulitis due to documented Vibrio vulnificus inf Cellulitis due to documented Vibrio vulnificus infection. (Image courtesy of Kepler Davis.)
  • Lymphangitic spread (red lines streaking away from the area of infection), crepitus, and hemodynamic instability are indications of severe infection, requiring more aggressive treatment

  • Circumferential cellulitis or pain that is disproportional to examination findings should prompt consideration of severe SSTI

The IDSA indicates that the following are also signs/symptoms of potentially severe deep SSTI (Note: these frequently appear later in the course of necrotizing infections), which necessitate emergent surgical evaluation [4] :

  • Violaceous bullae

  • Cutaneous hemorrhage

  • Skin sloughing

  • Skin anesthesia

  • Rapid progression

  • Gas in the tissue