Cellulitis: Early Signs, Diagnosis & Treatment Strategies

Learning Opportunities: Cellulitis 101

Meet Dr. Ryan, a primary care physician who starts his morning with a patient in distress.

Sarah, a 50-year-old woman with a history of diabetes, presents with redness and swelling in her lower leg that has worsened over the past two days.

Sarah’s Complaint:
“I noticed a small cut on my leg last week, but now my whole calf is red, swollen, and painful. I feel feverish and exhausted. What’s happening?”

Dr. Ryan performs a thorough physical exam and quickly suspects cellulitis.

…but what is Cellulitis?

The two main agents associated with this disease are 𝘚𝘵𝘳𝘦𝘱𝘵𝘰𝘤𝘰𝘤𝘤𝘶𝘴 𝘱𝘺𝘰𝘨𝘦𝘯𝘦𝘴 and 𝘚𝘵𝘢𝘱𝘩𝘺𝘭𝘰𝘤𝘰𝘤𝘤𝘶𝘴 𝘢𝘶𝘳𝘦𝘶𝘴 🦠.

Differential diagnosis:

When evaluating a patient with skin erythema and swelling, it’s essential to consider various conditions that may present similarly but differ in severity, management, and prognosis.

Below is a quick comparison of key features and differentiating factors to help guide your clinical reasoning:

It is Cellulitis, now what?

Management & Antibiotic Coverage:

For mild or uncomplicated cases:

• If purulence is present, cover for CA-MRSA:

  • Trimethoprim/sulfamethoxazole (TMP/SMX) 1 BID

  • Doxycycline 100 mg BID

  • Clindamycin 300–450 mg TID-QID

• 7-10 days of therapy is typically sufficient, based on clinical responses

Severe cases or infections with systemic involvement often require IV antibiotics and inpatient care, especially for patients with venous stasis or immunosuppression.

To help you better recognize and manage this common skin infection, we’ve created a FREE physical exam checklist designed for quick reference during clinical assessments.

This resource walks you through the key signs, symptoms, and physical findings of cellulitis, so you can confidently evaluate severity, identify potential complications, and guide your treatment decisions.

Want to master the diagnosis and treatment of cellulitis and other bacterial diseases? Our course covers everything you need to know + an in-depth treatment segment.

Check it out here