What Is Cellulitis?

Cellulitis is a bacterial skin infection that affects the deeper layers of the skin and the underlying tissues. It is most often characterized by redness, warmth, swelling, and tenderness in the affected area. While it can appear anywhere on the body, it most commonly affects the lower legs and feet.

The condition occurs when bacteria—typically Streptococcus or Staphylococcus aureus—enter the skin through breaks such as cuts, burns, ulcers, or insect bites. Prompt medical attention and antibiotic treatment usually resolve the infection, but if left untreated, cellulitis can spread and lead to serious complications.

Common Symptoms

Symptoms of cellulitis can vary, but most patients will experience:

  • Redness or discoloration

  • Warmth at the site of infection

  • Swelling or puffiness

  • Tenderness or pain

  • Blisters or skin dimpling (peau d’orange appearance)

More severe cases may present with:

  • Fever and chills

  • Fatigue or malaise

  • Swollen lymph nodes near the infected area

  • Nausea or body aches

Cellulitis usually develops rapidly and tends to spread if not treated. If pain intensifies suddenly or the area becomes numb, it could indicate a serious condition such as compartment syndrome, requiring immediate care.

What Causes Cellulitis?

Cellulitis develops when bacteria breach the skin’s protective barrier. Common bacteria responsible include:

  • Group A Streptococcus

  • Staphylococcus aureus, including MRSA (methicillin-resistant strain)

The bacteria may enter through:

  • Cuts or abrasions

  • Insect or animal bites

  • Surgical wounds

  • Skin conditions like eczema or athlete’s foot

  • Needle punctures or IV drug use

In healthy individuals, the immune system usually fights off minor invasions. However, some people are more vulnerable to infection.

Risk Factors

Several conditions or lifestyle factors increase the risk of cellulitis:

  • Age over 50

  • Poorly managed diabetes

  • Obesity

  • Compromised immune system (due to medications or illnesses)

  • HIV/AIDS

  • Chronic skin conditions (eczema, tinea pedis)

  • Lymphedema

  • Poor circulation

  • Recent surgery or trauma

  • Living in crowded conditions (military, prison, nursing home)

  • Active IV drug use

How It's Diagnosed

A healthcare provider will often diagnose cellulitis through a physical exam and discussion of symptoms and medical history. Be sure to mention any injuries or insect bites near the affected area.

While no specific lab test confirms cellulitis, your provider may order:

  • Wound culture: To determine the specific bacteria involved

  • Blood tests: To identify signs of systemic infection

  • Imaging tests: To check for deep tissue involvement or abscess formation

If the diagnosis is unclear or symptoms don’t improve with standard treatment, you may be referred to a dermatologist.

Treatment Options

Antibiotics are the primary treatment for cellulitis. Most people can be treated with oral antibiotics at home. Common choices include:

  • Cephalexin

  • Dicloxacillin

  • Clindamycin

  • Amoxicillin-clavulanate

In more severe or facial infections, IV antibiotics may be required in a hospital setting. Treatment typically lasts 7–14 days depending on severity and response.

Other supportive measures include:

  • Resting the affected limb

  • Elevating the area to reduce swelling

  • Keeping wounds clean and covered

In rare cases, surgical drainage or debridement may be necessary if abscesses or necrotic tissue develop.

Preventing Cellulitis

While cellulitis can’t always be avoided, the following steps can significantly reduce your risk:

  • Practice good hygiene: Wash hands frequently and bathe regularly

  • Protect skin from injury: Wear protective clothing and shoes

  • Treat wounds promptly: Clean cuts or bites, apply antiseptic, and keep them bandaged

  • Moisturize skin: Prevents dryness and cracking

  • Manage chronic conditions: Keep diabetes and eczema under control

  • Avoid sharing personal items: Towels, razors, or nail clippers

Possible Complications

Although cellulitis usually resolves with proper treatment, it can lead to complications if untreated or severe:

  • Abscesses: Collection of pus requiring drainage

  • Bacteremia: Bacteria entering the bloodstream

  • Osteomyelitis: Bone infection

  • Endocarditis: Heart valve infection

  • Sepsis: A life-threatening body-wide infection

  • Chronic swelling or scarring

Seek emergency care if you notice:

  • Rapidly spreading redness or streaking

  • Severe pain or swelling

  • High fever or chills

  • Dizziness or confusion

Living With Cellulitis

Most individuals recover completely after starting antibiotics, often within a few days. However, recurrence is possible, especially in people with risk factors. Up to 18% of patients may require a second course of antibiotics.

Tips for recovery and long-term management:

  • Finish all prescribed medication

  • Monitor for return of symptoms

  • Wear compression socks if recommended

  • Follow up with your provider if symptoms persist

  • Improve lifestyle habits (diet, hygiene, chronic disease management)

Ongoing care and early treatment at the first signs of recurrence can help prevent complications and reduce the frequency of repeat infections.