Cellulitis Evaluation Online

What Is Cellulitis — and How Is It Diagnosed?

Cellulitis is a bacterial skin infection that affects the deeper layers of skin and the tissue beneath it. It shows up as a spreading area of redness, swelling, warmth, and tenderness — most often on the lower legs.

The most common causes are Streptococcus and Staphylococcus aureus bacteria (including MRSA in some cases). You may be at higher risk if you have:

• Breaks in the skin — cuts, wounds, insect bites, athlete's foot, or eczema
• Swelling in the legs (lymphedema or poor vein circulation)
• Obesity or diabetes

A related condition called erysipelas is a more surface-level skin infection. It has a sharp, raised, shiny red border and usually appears on the lower leg or face.

Cellulitis is diagnosed based on how it looks and your symptoms — not blood tests. Blood cultures come back positive in fewer than 4% of cases. The more important concern is making sure it is not something more serious, like necrotizing fasciitis (a fast-spreading, life-threatening deep tissue infection that can look like cellulitis early on).

Our board-certified provider evaluates potential cellulitis through video and photo review, along with a detailed history. To help with your visit:

• Take photos of the red area, ideally with the borders outlined in pen to track whether it spreads
• Note how fast the redness is growing
• Be ready to share your fever status, prior similar episodes, diabetes history, immune health, and any history of MRSA

Your provider will use clear clinical criteria to decide if you can be safely treated at home with oral antibiotics, or if you need in-person or emergency care instead.

Clinical Features of Cellulitis We Evaluate

Antibiotics for Cellulitis & Telehealth Limitations

For mild-to-moderate cellulitis without pus, fever, or serious health conditions, oral antibiotics taken at home are the standard treatment. First-line options per IDSA guidelines include:

• Cephalexin 500 mg four times daily for 5–7 days
• Dicloxacillin 500 mg four times daily for 5–7 days
• Clindamycin — an alternative if you are allergic to penicillin-type antibiotics
• TMP-SMX (Bactrim DS) — used when MRSA is a concern (prior MRSA, abscess present, healthcare exposure, or failed first-line antibiotics)

Important telehealth limitations: There are things a virtual visit cannot fully assess. These include:

• Abscess — a pocket of pus that needs to be drained, not just treated with antibiotics. This requires a hands-on exam to detect.
• Deep tissue infections (necrotizing fasciitis, gas gangrene) — these need in-person exams, lab work, and often imaging (CT or MRI).
• Blood clot (DVT) — a common mimic of cellulitis that causes similar redness, swelling, and warmth in one leg. It requires an ultrasound to rule out and is treated with blood thinners, not antibiotics.

Your provider will assess the severity of your cellulitis using established IDSA criteria. Mild cases (no fever, no serious health issues) can be safely managed via telehealth. More severe cases — with fever, rapid spread, or weakened immune system — need in-person care, and your provider will direct you immediately. A follow-up within 48–72 hours is recommended for all telehealth-managed cellulitis. If you are not improving, you will need an in-person evaluation.