Cellulitis

Key Features

Essentials of Diagnosis

• Edematous, expanding, erythematous, warm plaque with or without vesicles or bullae

• Lower leg is frequently involved

• Pain, chills, and fever are commonly present

• Septicemia may develop

General Considerations

• Usually due to gram-positive cocci, though gram-negative rods or even fungi can produce similar picture

• The major portal of entry for lower leg cellulitis is toe web tinea pedis with fissuring of the skin at this site

• Erysipelas is a superficial form of cellulitis that occurs classically on the cheek, caused by β-hemolytic streptococci (see Erysipelas)

Clinical Findings

Symptoms and Signs

• Lesion begins as a small batch and expands over hours

• Edematous, expanding, erythematous, warm plaque with or without vesicles or bullae

• Pain at the lesion, malaise, chills, and moderate fever

• Usually on the lower leg

• Lymphangitis and lymphadenopathy may be present

• Progressive chills, fever, and malaise

• Septicemia and septic shock may develop

Differential Diagnosis

• Deep venous thrombosis

• Venous stasis

• Candidiasis

• Anthrax

• Contact dermatitis

• Herpes zoster (shingles)

• Scarlet fever

• Angioedema

• Necrotizing fasciitis

• Sclerosing panniculitis

• Underlying osteomyelitis

• Systemic lupus erythematosus

• Erysipeloid

Diagnosis

Laboratory Tests

• Attempts to isolate the responsible organism by injecting and then aspirating saline are successful in 20% of cases

• Leukocytosis and an increased sedimentation rate are almost invariably present but are not specific

• Blood cultures may be positive

• Skin biopsy is particularly helpful in an immunocompromised patient whose cellulitis may be due to an uncommon organism

Diagnostic Procedures

• ALT-70 is a predictive model to diagnose cellulitis or a cellulitis mimic and to provide guidance about when a dermatology consultation is needed

  • Variables are

    • Asymmetry (3 points)

    • Leukocytosis of 10,000/mcL or more at presentation (2 points)

    • Tachycardia above 90 beats per minute (1 point)

    • Age 70 years or older (1 point)

  • Score above 5 carries more than an 82% chance of a true cellulitis while a score below 2 suggests a greater than 83% chance of a cellulitis mimicker

Treatment

Medications

• Intravenous or parenteral antibiotics effective against group A β-hemolytic streptococci and staphylococci may be required for the first 24–48 hours

• Dicloxacillin or cephalexin, 250–500 mg four times daily orally for 5–10 days, is usually adequate for mild cases or following initial parenteral therapy

• In patients in whom intravenous treatment is not instituted, the first dose of oral antibiotic can be doubled to achieve rapid high blood levels

• Oral penicillin 250 mg twice daily or oral erythromycin 250–500 mg twice daily can decrease the risk of recurrence in patients with recurrent lower leg cellulitis (three to four ...