Introduction
Cellulitis and erysipelas are bacterial skin infections resulting from the bacteria inoculating the skin through cuts or sores. It is challenging to differentiate between cellulitis and erysipelas. Although cellulitis and erysipelas share similarities, the two conditions are different entities. The main differentiating feature is cellulitis causes deeper skin infections, but erysipelas causes superficial skin infections. Understanding the two terms is vital for disease diagnosis and effective treatment.
What Is Cellulitis?
Cellulitis is a common skin condition where the spread of bacteria causes skin inflammation. Streptococcus and Staphylococcus are common bacteria causing cellulitis. Other causative organisms are Streptococcus pneumoniae, Haemophilus influenza, gram-negative bacilli, and anaerobes. Staphylococcus aureus often develops around wounds, abscesses, furuncles (boils), or carbuncles (painful boil clusters), causing purulent cellulitis. Although cellulitis could affect any body part, the commonly involved areas are legs, digits, face, hands, torso, neck, and buttocks.
Risk Factors
Individuals with venous insufficiency, trauma, obesity, chronic edema, or lymphedema, and patients with a history of cellulitis, immunosuppression, ulcers, wounds, dermatophytic infections, or cutaneous inflammation are at higher risk for developing cellulitis. Other causes are animal bites, chemotherapy, neutropenia, and immersion injuries.
Symptoms
Pain, redness, warmth, and advancing borders are presenting symptoms. Affected individuals develop tender skin with edema, fever, lymphadenopathy, or bullae. Rarely, (infection of the lymphatic channel) develops in affected patients. The condition often develops near skin breaks, surgical wounds, trauma, tinea infection, ulceration, and occasionally in normal skin. Around 40 percent of affected individuals also present with systemic illness.
Diagnosis
Most cases are identified through history and clinical examination. Isolating the disease-causing bacteria is difficult, but testing the blood culture or aspirated fluid from the inflammation site may help. Affected individuals may develop a fever and an elevated white blood cell count. Ultrasound imaging helps identify cellulitis and rule out abscesses, deep vein thrombosis, or foreign bodies.
Treatment
Most cases of cellulitis are provided empiric treatment with penicillinase-resistant penicillin, first-generation cephalosporin, amoxicillin-clavulanate, macrolide, or fluoroquinolone. The antibiotic treatment is given for an additional three days, even after symptoms are settled. Diseases involving smaller skin areas are treated orally, but extensive skin involvement needs parenteral therapy. Superficial cellulitis improves within one day of starting treatment, but individuals with deep dermis involvement require several days of parenteral antibiotic therapy. Extensive skin involvement requires evaluation with plain radiographs or surgical debridement to rule out gas gangrene, osteomyelitis, and necrotizing fasciitis (flesh-eating disease). Adjunctive therapy for cellulitis is a cool compress, analgesic for pain, tetanus injection, immobilization, and elevation of the affected limb.
In diabetic patients, immunocompromised, young children, or individuals with infection unresponsive to treatment, third-generation Cephalosporins are the treatment of choice. Recurrent episodes of cellulitis can compromise venous and lymphatic circulation and cause dermal fibrosis, lymphedema, epidermal thickening, and recurrent episodes of cellulitis.
Types
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Periorbital cellulitis is a common condition in children. The condition is often associated with sinusitis. If the affected child appears toxic and febrile, the doctors suggest a blood culture and lumbar puncture. It is treated with warm soaks, oral antibiotics, and follow-up.
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Orbital cellulitis develops when bacterial infection crosses the orbital septum. The presenting symptoms are orbital pain, proptosis (bulging eyes), restricted eye movement, visual disturbance, and sinusitis. If the infection remains untreated, patients can develop abscesses, blindness, diplopia (double vision), limited eye movement, or meningitis (inflammation of the meninges). Orbital cellulitis is a severe and emergency condition and requires intravenous antibiotics. Affected patients must get an ophthalmic consultation and CT (computed tomography) scan to rule out pre-septal infection.
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Perianal cellulitis is a common condition affecting children and is caused by group A beta-hemolytic streptococcus. The presenting complaints are dermatitis (skin inflammation), rectal pain, itching, and blood-streaked stools. The median age for developing an infection is 4.5 years. Even if the infection is cured with oral antibiotics, the recurrence rate of infection is high.
What Is Erysipelas?
Erysipelas is a bacterial skin infection, which is also called St. Anthony fire. The condition affects superficial skin and has prominent lymphatic involvement. The commonly affected areas are the face and extremities. If erysipelas develop on the face, it may have spread from the nasal passage following infection in the throat or nose. Infection in extremities develops due to a break in the skin barrier, which serves as a portal of entry for bacteria.
Causes
Beta-hemolytic streptococcus causes erysipelas. Any condition that prevents the fluid or blood from draining from wounds may cause erysipelas to develop. Erysipelas develops in young children, individuals with weakened immune systems, surgical incisions, skin ulcers, psoriasis or other skin conditions, insect or animal bites, diabetics with foot infections, swollen legs, and those injecting themselves with drugs.
Symptoms
The condition presents as an erythematous infection with clear demarcation of the margins and is often associated with lymphatic streaking. The lesions appear to be raised above the surface of adjacent skin. Additionally, there is marked edema and bleb formation. Most cases of erysipelas do not present with wounds or skin lesions but develop preceding influenza-like symptoms. In facial involvement, the eye becomes shut. There can be central resolution of lesions while they continue to expand peripherally. Some patients develop fever, chills, and toxicity due to infection.
There is an increase in reported cases of erysipelas among children, the elderly, diabetes patients, alcoholics, lymphedema patients, and individuals with compromised immune systems.
Treatment
Erysipelas are treated with a standard dose of oral or intravenous penicillin. Individuals with face infections must chew or speak as little as possible.
What Are the Differentiating Features of Erysipelas and Cellulitis?
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Erysipelas is a superficial skin infection involving the dermis and superficial lymph vessels. Cellulitis is a skin infection of deeper tissues affecting subcutaneous fat and deep dermis layers and may cause pus to develop.
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The distinction of the affected skin is sharp in erysipelas but poor in cellulitis.
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Streptococcus bacteria alone is the cause of erysipelas, although infections with Staphylococcus or Streptococcus bacteria can also cause cellulitis.
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The subcutaneous tissue involvement is seen in cellulitis but absent erysipelas.
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The symptoms of being unwell and having a fever are more common in erysipelas. However, similar symptom occurs in severe cellulitis.
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The spread of pus-producing infection or abscess is typical in cellulitis. Lymphedema is common in erysipelas infection.
Conclusion
Cellulitis and erysipelas differ based on infection location, lesion appearance, causative agent, and symptoms. Cellulitis infects the deeper skin layer and has an advancing border. Erysipelas affects superficial skin and have a well-demarcated border. Understanding the difference aids in effective disease management. Both these bacterial skin infections require medical attention. Appropriate antibiotic therapy is crucial for successful management and prevention of complications.
