Diagnosis

Cellulitis

Etiology

Cause - organisms on the skin [9ml]

• Streptococcus pyogenes

• Group A Streptococcus

• Staphylococcus aureus

• Streptococcus pneumoniae

Pathophysiology [9ml][u7q]

• Breach in the skin (cut, blister, burns, insect/animal bite, surgical wound, intravenous drug injection) --> gain entrance to the dermis --> multiply --> cellulitis

Risk factors [9ml]

• Elderly

• Diabetes mellitus

• Immunodeficiency

• Cancer

• Venous stasis

• Chronic liver disease

• Peripheral arterial disease

• Chronic kidney disease

Complications [u7q]

• Sepsis

• Endocarditis

• Osteomyelitis

Epidemiology

Incidence per 100.000 [6ed][ywd][dmo]

Approach

• Blood test

• Blood culture (MRSA?)

• Needle aspiration

• Biopsy

• Ultrasound

• CT

Treatment

1. Antibiotic treatment based on microbe and clinical status [9ml]

   • Cephalexin 500 mg every 6 hours

   • Clindamycin 300 mg to 450 mg every 6 hours

2. Drainage if abscess

3. Admission or ICU if systemically ill, orbital cellulitis, immunosuppressed, necrotizing infection, or organ failure

Differential diagnoses

Burn wound, Chronic venous insufficiency, Contact dermatitis, Cutaneous anthrax, Cutaneous metastasis, Cutaneous T-cell lymphoma, Deep venous thrombosis, Drug eruptions, Erysipelas, Erysipeloid, Erythema multiforme, Gas gangrene, Gout, Graft-versus-host disease, Hidradenitis suppurativa, Impetigo, Insect Bite, Leukemia cutis, Mycosis fungoides, Myiasis, Myonecrosis calciphylaxis, Necrotizing fasciitis, Neutrophilic eccrine hidradenitis, Nocardiosis, Osteomyelitis, Pyoderma gangrenosum, Septic arthritis, Stevens-Johnson syndrome, Sweet syndrome, Thrombophlebitis, Wells' syndrome