What Is Cellulitis?

Cellulitis is a common and sometimes painful skin condition caused by a bacterial infection. It affects the dermis (the inner layer of your skin) and the subcutaneous tissues underneath. The infection causes redness, swelling, warmth, and tenderness in the affected area, typically the legs or feet, though it can occur anywhere on the body.

An estimated 14 million cases are diagnosed in the United States each year, making it one of the most frequent reasons for skin-related doctor visits. While cellulitis can look alarming, it generally responds well to antibiotics when diagnosed early and treated properly.

The bacteria usually gain access to deeper layers of skin through cuts, insect bites, burns, surgical wounds, or other types of skin breakdown. People over age 50 and those with chronic health conditions are at higher risk of developing cellulitis.

Key Symptoms to Recognize

Cellulitis presents with a range of localized and systemic symptoms. A proper diagnosis usually requires at least two of the following signs:

  • Redness (erythema)

  • Swelling (edema)

  • Warmth at the infection site

  • Tenderness or pain

In addition to these primary signs, some people may notice:

  • Skin that appears tight, shiny, or stretched

  • Blistering in the affected area

  • Peau d’orange — a texture that resembles an orange peel

Systemic symptoms can include fever, chills, fatigue, and swollen lymph nodes near the infected area. The skin often becomes increasingly painful over time, especially if the infection spreads.

If you notice sudden severe pain, numbness, or discoloration, this may suggest complications such as compartment syndrome — a dangerous condition that requires immediate medical attention.

Common Causes of Cellulitis

The root cause of cellulitis is bacterial invasion into the skin's lower layers and tissues. This usually happens after an opening in the skin allows bacteria to enter. The immune system’s reaction to the invading organisms causes inflammation, redness, and swelling.

The most frequent bacterial culprits include:

  • Group A Streptococcus (GAS): Responsible for the majority of cases

  • Staphylococcus aureus, including MRSA (Methicillin-resistant Staph aureus): More likely in recurrent or severe infections

Risk of infection increases in situations where skin integrity is compromised. These include:

  • Insect bites or stings

  • Animal bites

  • Surgical incisions

  • Burns and ulcers

  • IV drug use or injections

Even everyday nicks and cuts can lead to cellulitis if bacterial exposure is high or if the immune response is compromised.

Risk Factors

Several underlying conditions and lifestyle habits may predispose individuals to cellulitis:

  • Age over 50

  • Uncontrolled diabetes

  • Eczema or athlete’s foot

  • Immune suppression (e.g., due to HIV, AIDS, or medications)

  • Chronic liver or kidney disease

  • Poor circulation or peripheral artery disease

  • Lymphedema

  • Obesity

  • Living in long-term care facilities or prisons

  • Participating in contact sports

  • History of previous cellulitis

Each of these factors either increases bacterial exposure or weakens the skin’s ability to protect against infection.

How It’s Diagnosed

In most cases, healthcare providers diagnose cellulitis through a physical exam and patient history. They’ll assess the size, shape, and condition of the affected skin and may ask questions like:

  • When did symptoms begin?

  • Have you had any recent injuries or bites?

  • Are you experiencing fever or chills?

Imaging tests or blood work are not usually necessary unless the infection appears severe, fails to respond to treatment, or spreads rapidly. In some cases, lab tests might be ordered to identify the type of bacteria or rule out other causes of skin inflammation.

If diagnosis is unclear, a referral to a dermatologist may be needed. Dermatologists specialize in skin conditions and can help confirm the presence of cellulitis versus other look-alike conditions such as contact dermatitis or venous stasis dermatitis.

Treatment Options

The primary treatment for cellulitis is a course of antibiotics. In most cases, oral antibiotics are effective and begin working within 24–48 hours. Commonly prescribed medications include:

  • Cephalexin

  • Dicloxacillin

  • Clindamycin

  • Doxycycline (especially for MRSA)

Hospitalization and intravenous (IV) antibiotics may be required in cases where:

  • The infection affects the face

  • The patient has a compromised immune system

  • Oral antibiotics fail

  • There’s a rapid spread of symptoms

Supportive measures are also important:

  • Elevation: Raising the affected limb helps reduce swelling.

  • Rest: Allow your body time to recover by limiting physical activity.

  • Hydration: Drink plenty of water to support your immune system.

  • Pain relief: Over-the-counter medications like acetaminophen or ibuprofen can ease discomfort.

In very rare situations involving tissue damage or abscesses, surgical drainage or debridement may be necessary.

Preventing Cellulitis

Fortunately, cellulitis can often be prevented by protecting and caring for your skin properly. Key steps include:

  • Protect your skin: Wear appropriate clothing and gloves when gardening, handling tools, or participating in sports.

  • Manage wounds quickly: Clean cuts and scrapes with soap and water, apply antibiotic ointment, and keep the area bandaged.

  • Control chronic conditions: Keep diabetes, eczema, and athlete’s foot under control.

  • Stay hygienic: Wash hands regularly and moisturize skin to prevent cracks or dryness.

  • Avoid shared needles: Never reuse or share needles for injections, tattooing, or any other reason.

People with a history of cellulitis should take extra precautions and speak with a healthcare provider about preventive antibiotics if the infections become recurrent.

Possible Complications

Though most cases resolve without serious problems, cellulitis can sometimes lead to complications, especially if left untreated. These may include:

  • Abscess formation: Pockets of pus may develop beneath the skin

  • Bacteremia: The bacteria enter the bloodstream, leading to sepsis

  • Osteomyelitis: Infection spreads to the bone or bone marrow

  • Endocarditis: Infection of the heart’s inner lining

  • Septic arthritis: Involvement of the joints

  • Lymphangitis: Inflammation of the lymphatic vessels

  • Necrotizing fasciitis (in very rare cases): A life-threatening soft tissue infection

Early diagnosis and prompt antibiotic therapy greatly reduce the risk of these complications.

Recovery and Living With Cellulitis

Recovery typically begins within a few days of starting antibiotic treatment, but full healing may take one to two weeks depending on the severity and location. During this time:

  • Monitor the infected area closely for signs of worsening

  • Finish your full antibiotic course even if symptoms improve early

  • Contact your provider if the infection seems to be spreading or symptoms don’t improve

About 18% of people may not respond to their first round of antibiotics. In such cases, your doctor may prescribe a different medication or investigate other underlying issues.

For people who have had cellulitis once, the risk of recurrence is higher. If you fall into this group, consistent skin care, chronic condition management, and wound prevention are vital to avoiding future infections.

When To See a Doctor

Seek medical attention if you experience:

  • Sudden, severe pain or numbness in the area

  • Red streaks spreading from the infection

  • Rapidly worsening symptoms

  • High fever or chills

  • Swelling near the eyes or on the face

Early treatment can prevent complications and minimize recovery time.

Cellulitis vs Other Skin Conditions

Cellulitis can sometimes be mistaken for other issues, including:

  • Contact dermatitis

  • Venous insufficiency

  • Deep vein thrombosis (DVT)

  • Erysipelas (a more superficial bacterial skin infection)

  • Gout

If symptoms do not improve with antibiotics, or worsen, your doctor may revisit the diagnosis and suggest additional testing.

Final Thoughts

Cellulitis is a common and treatable skin condition. With proper care and attention, most people recover fully without complications. The key is early recognition, appropriate treatment, and preventive strategies to reduce your risk of future episodes. If you notice redness, swelling, and tenderness in any area of your skin, especially after an injury or bite, don’t wait to consult a healthcare provider.