Acute contact dermatitis can cause redness and swelling, but it is distinguished by intense pruritus and often vesicles or weeping, which are not typical of cellulitis.
This is deep dermal swelling without the prominent erythema, warmth, or tenderness of an infectious cellulitis, and it does not respond to antibiotics.
These present as a cellulitis-like erythema but are distinguished by their firm, indurated feel and their association with an underlying malignancy (often breast cancer).
The classic "bull's-eye" rash of Lyme disease is an expanding annular patch that is typically asymptomatic and not tender or warm like cellulitis.
This is a panniculitis (inflammation of fat), presenting as multiple, deep, exquisitely tender nodules on the shins, rather than a spreading superficial erythema.
This can cause a unilateral, erysipelas-like plaque on the lower leg, but it is distinguished by its recurrent nature in the setting of episodic fevers and serositis.
This is a recurrent, sharply demarcated, dusky red plaque that appears in the same spot after taking a specific drug.
Gouty cellulitis presents as intense erythema over a joint (classically the big toe), but it is due to crystal deposition and is distinguished by an underlying acute arthritis.
Before vesicles appear, zoster can present as unilateral pain and erythema, but it is defined by its strict dermatomal distribution and subsequent vesicular eruption.
Subcutaneous GA presents as non-tender nodules, not a warm, spreading plaque of erythema.
This presents as an expanding, indurated plaque with a characteristic lilac-colored inflammatory border, a much more chronic and sclerotic process than acute cellulitis.
An exaggerated bite reaction is distinguished by a central punctum and intense pruritus, which is not a primary feature of cellulitis.
This presents as linear cords or plaques ("the rope sign") and is associated with autoimmune disease, a different morphology and context.
This is a chronic fibrosing panniculitis of the lower legs, presenting with indurated, bound-down skin and an "inverted champagne bottle" leg shape, a chronic state unlike acute cellulitis.
This presents as deep, tender nodules or plaques and is distinguished by a biopsy showing a neutrophilic infiltrate in the fat.
This is a phototoxic reaction presenting as bizarre, linear, or streaky erythema and blisters in a pattern of contact with a photosensitizing plant.
This is a specific syndrome of recurrent, painless, fiery-red erythema in the perineum associated with toxin-producing bacteria.
This is an acute neutrophilic dermatosis presenting with fever and tender, succulent, reddish-purple plaques or nodules, often with a pseudovesicular appearance.
This is inflammation of a vein, distinguished by a palpable, tender, linear cord along the course of the vein, which is not present in diffuse cellulitis.
This is a painful, often symmetric erythema, especially of the hands and feet, with a clear temporal relationship to chemotherapy administration.
Also known as eosinophilic cellulitis, this presents as a recurrent, itchy, cellulitis-like plaque and is distinguished by the presence of peripheral eosinophilia and eosinophils on biopsy.
