Pediatric Cellulitis

  • Etiology: Disruption of the skin and invasion of the subcutaneous tissues by bacteria leading to acute infection of the dermis and subcutaneous tissues without deep fascial or muscular involvement
  • Imaging US:
    — Abnormal echogenicity and increased thickness of dermis with indistinct haziness and increased echogenicity of the subcutaneous tissue
    — Progressive accumulation of edema in subcutaneous tissue appears as branching and anechoic striations which impart a lobulated “cobble-stone” appearance
  • Imaging MRI: Useful for distinguishing cellulitis alone from necrotizing fasciitis and infectious myositis and for showing subcutaneous fluid collections and abscesses
    — T1WI: Low signal
    — T1WI post contrast: Enhances
    — T2WI: Thickening of skin and superficial fascia with diffuse subcutaneous linear or reticular or ill-defined hyperintensity collecting at hypodermis
  • DDX:
  • Complications: If infection spreads to deeper tissues it can result in soft-tissue abscess, necrotizing fasciitis, infectious myositis, osteomyelitis, sepsis
  • Treatment: Antibiotics
  • Clinical: Presents with pain and skin erythema without well defined border and edema and warmth

Radiology Cases of Cellulitis

Radiology Cases of Cellulitis of the Abdominal Wall

CT and MRI of osteomyelitis of the rib
Axial CT without contrast of the chest (above) shows bilateral axillary adenopathy and soft tissue swelling over the left lateral chest wall and associated rib destruction. Coronal T2 MRI of the chest (below left) shows a high signal intensity fluid collection between the skin and the ribs with surrounding edema. Axial T1 MRI with contrast of the chest (below right) shows extensive enhancement of the left ribs and surrounding muscle.

Radiology Cases of Cellulitis of the Lower Extremity

MRI of pediatric cellulitis of the lower extremity
Two non-contiguous axial T2 MRI images of the right lower extremity show diffuse circumferential high T2 signal in the subcutaneous tissues and along the deep fascial plane. There were no abscesses seen.