Distinguishing cellulitis from its mimics.

August 2012

Keller EC, Tomecki KJ, Chadi Alraies M.

Source

FACP, Department of Hospital Medicine, A13, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; alraiec@ccf.org.

Key points

Cellulitis is rarely bilateral.

Patients with cellulitis often have systemic symptoms, such as fever and leukocytosis.

A chronic course points to a diagnosis other than cellulitis.

Plaques with a “bound-down” appearance or dark pigmentation point to a chronic disease rather than cellulitis.

Stasis dermatitis is the most common mimic of cellulitis.

MORE THAN 10% OF PATIENTS labeled as having cellulitis do not have cellulitis.¹ This is unfortunate, as it leads to excessive and incorrect use of antibiotics and to delays in appropriate therapy.²However, it is not surprising, given the number of conditions that bear a striking similarity to cellulitis. A familiarity with the features of true cellulitis and with the handful of conditions that can bear a striking similarity to it is the way out of this potential diagnostic quagmire.

Abstract

Distinguishing true cellulitis from its many imitators is challenging but critical if we are to avoid unnecessary use of antibiotics and delays in treatment. Common imitators of cellulitis are stasis dermatitis, lipodermatosclerosis, contact dermatitis, lymphedema, eosinophilic cellulitis, and papular urticaria. Specific criteria do not exist for the diagnosis of cellulitis, but the alert physician can find clues in the history and physical examination that point toward cellulitis.

WHAT CELLULITIS IS—AND IS NOT

The key characteristics of cellulitis are redness, warmth, tenderness, and swelling of the skin. A history of trauma and pain in the affected area and evidence of leukocytosis³ suggest cellulitis. A symmetric or diffusely scattered pattern indicates a condition other than cellulitis, which is overwhelmingly unilateral, with smooth, indistinct borders^4,5 Other factors pointing to cellulitis are underlying immunosuppression, a more rapid progression, previous episodes, systemic symptoms (eg, fever, leukocytosis), new medications, new travel or outdoor exposure, and comorbidities such as diabetes and peripheral vascular disease. A long-standing, slowly progressive course and a history of unsuccessful treatment with antibiotics are strong indicators of a condition other than cellulitis.

Consultation with a dermatologist is recommended to narrow the differential diagnosis. The dermatologist can determine if biopsy is necessary, as many dermatoses that mimic cellulitis can be diagnosed by visual recognition alone.

Important full text article: Cleveland Clinic Journal of Medicine