What are the signs and symptoms of cellulitis?

Signs and Symptoms of Cellulitis

Cellulitis presents as rapidly spreading areas of erythema (redness), swelling, tenderness, and warmth with poorly defined borders, often accompanied by lymphangitis and regional lymph node inflammation. 1

Primary Clinical Features

The cardinal signs of cellulitis include:

• Erythema (redness) that spreads diffusely across the affected skin area 1, 2
• Swelling (edema) of the involved tissue 1, 2
• Tenderness and pain over the affected area 1, 3
• Warmth to touch at the site of infection 1, 2
• Poorly defined borders distinguishing it from erysipelas, which has well-demarcated edges 2

Additional Cutaneous Manifestations

Beyond the primary features, cellulitis may present with:

• "Peau d'orange" appearance (orange peel texture) due to superficial cutaneous edema surrounding hair follicles, causing skin dimpling where follicles remain tethered to the underlying dermis 1, 2
• Vesicles or bullae (fluid-filled blisters) that may develop on the skin surface 1
• Cutaneous hemorrhage manifesting as petechiae or ecchymoses 1
• Lymphangitis (red streaking along lymphatic vessels) 1, 2
• Regional lymph node inflammation with tenderness and enlargement 1, 2

Systemic Signs and Symptoms

While typically mild, systemic manifestations can occur and include:

• Fever 1, 2
• Tachycardia (rapid heart rate) 1, 2
• Confusion or altered mental status 1, 2
• Hypotension (low blood pressure) 1, 2
• Leukocytosis (elevated white blood cell count) 1, 2

Important caveat: These systemic features may appear hours before the skin abnormalities become evident, which can complicate early diagnosis. 1

Critical Diagnostic Distinction

Cellulitis refers specifically to diffuse, superficial, spreading skin infections—NOT cutaneous inflammation associated with collections of pus. 1 The term should not be used for:

• Septic bursitis 1
• Furuncles (boils) 1
• Skin abscesses 1

This distinction is clinically crucial because cellulitis requires antimicrobial therapy as primary treatment, whereas purulent collections require drainage as the major component of management. 1

Common Pitfalls in Diagnosis

Cellulitis is frequently misdiagnosed because numerous conditions present with similar findings. 3, 4 Common mimickers include:

• Venous stasis dermatitis 3, 4
• Contact dermatitis 3, 4
• Deep vein thrombosis 3
• Panniculitis 3
• Eczema 4
• Lymphedema 4

The Infectious Diseases Society of America emphasizes that cellulitis is a clinical diagnosis based on history and physical examination, with no gold standard diagnostic test available. 1, 4