From the Guidelines
CT imaging is indicated in cellulitis when there is suspicion of a deeper infection or complications that may not be apparent on physical examination, such as necrotizing fasciitis, abscess formation, or osteomyelitis, as evidenced by the most recent study in 2022 1.
Indications for CT Imaging
The following conditions warrant consideration of CT imaging in cellulitis:
- Signs of abscess formation, necrotizing fasciitis, or osteomyelitis
- Infection involving deep tissue planes
- Systemic toxicity
- Failure to respond to appropriate antibiotic therapy within 48-72 hours
- Rapidly spreading infection
- Concern for a foreign body
- Cellulitis of the face, orbital region, or neck where deep space infections can lead to serious complications
- Immunocompromised patients or those with diabetes, who have a higher risk of complicated infections
Benefits of CT Imaging
CT imaging allows clinicians to visualize fluid collections, gas formation, and tissue planes, enabling the identification of complications that require surgical intervention or drainage procedures that antibiotics alone cannot address, as supported by the study in 2022 1.
Clinical Judgment
While CT imaging can be useful, clinical judgment remains the most important element in diagnosis, and a high index of suspicion for deeper infections or complications is crucial, as emphasized in the 2014 guidelines 1.
From the Research
Indications for CT in Cellulitis
- CT scans are not typically indicated for the diagnosis of uncomplicated cellulitis, as the condition is usually diagnosed clinically based on symptoms and physical examination 2, 3, 4, 5.
- However, imaging studies such as CT or MRI may be helpful in certain situations, such as:
- Differentiating cellulitis from other conditions like necrotizing fasciitis or abscesses 6.
- Evaluating the extent of infection in complicated cases or in patients who are not responding to treatment.
- Identifying underlying conditions that may be contributing to the development of cellulitis, such as deep vein thrombosis or lymphedema 2, 3, 4, 5.
Specific Situations Where CT May be Indicated
- When there is suspicion of necrotizing fasciitis, CT or MRI can help differentiate this condition from cellulitis by identifying involvement of deep fasciae and other characteristic findings 6.
- In cases where the diagnosis is uncertain or the patient is not responding to treatment, CT or other imaging studies may be used to evaluate for complications or alternative diagnoses.