Cellulitis Diagnosis and Treatment

Clinical Characteristics

The American College of Physicians recommends that cellulitis is characterized by areas of erythema, swelling, tenderness, and warmth, with poorly defined borders, as opposed to erysipelas which has well-defined borders 1, 2
Cellulitis may present with lymphangitis and inflammation of regional lymph nodes, as well as a "peau d'orange" appearance due to superficial edema 1, 2
Systemic manifestations are typically mild, but may include fever, tachycardia, confusion, hypotension, and leukocytosis 1, 2

The Infectious Diseases Society of America recommends that blood cultures, tissue aspirates, or skin biopsies are not required for typical cases of cellulitis, but may be considered for patients with malignancy, severe systemic symptoms, or unusual predisposing factors 1, 2

The American College of Physicians recommends that cellulitis treatment should include antibiotics active against streptococci, which are the primary cause of cellulitis 1, 2
For uncomplicated cases, a 5-day course of antimicrobial therapy is as effective as a 10-day course if clinical improvement is seen at 5 days 1, 2
Elevation of the affected area can accelerate improvement by promoting gravity-driven drainage of edema and inflammatory substances 3

The Infectious Diseases Society of America recommends that patients receive therapy for any predisposing conditions, and consider descolonization with mupirocin or daily bathing with chlorhexidine or diluted bleach for recurrent cases 3, 4

Cellulitis typically shows poorly defined borders, a gradual onset over hours‑to‑days, and diffuse erythema of skin and subcutaneous tissue, whereas gout presents with a rapid onset (within hours) of severe pain that is often out of proportion to physical findings, and well‑localized joint involvement. 5
Gout most commonly involves the first metatarsophalangeal joint but can affect any joint; the inflammation is confined to the joint rather than producing diffuse skin changes. 5

Synovial fluid aspiration is the reference standard for confirming acute gout, as identification of monosodium urate crystals in the fluid provides a definitive diagnosis. 5
Pain severity in gout is frequently disproportionate to the observable joint findings, serving as a clinical clue to differentiate it from cellulitis. 6

For uncomplicated cellulitis, first‑line therapy consists of antibiotics targeting streptococci (e.g., penicillin, amoxicillin, or cephalexin). 7

Cellulitis typically presents with rapidly spreading erythema, swelling, warmth, and tenderness of the skin, with poorly defined borders that help differentiate it from erysipelas. 8
The onset is acute, developing over hours to days, and the erythema and swelling expand quickly. 8

An orange‑peel (“peau d’orange”) texture may appear due to superficial edema surrounding hair follicles, producing skin dimpling. 8
Vesicles or bullae can develop in some patients. 8
Cutaneous hemorrhage in the form of petechiae or ecchymoses may be observed. 8
Lymphangitis, manifested as red streaking that extends from the affected area toward regional lymph nodes, may occur. 8

Inflammation and tenderness of the regional lymph nodes that drain the affected area are common findings. 8

Development of hemorrhagic bullae (bullous changes with bleeding) signals a potential deeper or necrotizing infection and warrants urgent surgical consultation. 8