Eosinophilic cellulitis

Eosinophilic cellulitis, also known as Wells' syndrome (not to be confused with Weil's disease), is a skin disease that presents with painful, red, raised, and warm patches of skin.^[2] The rash comes on suddenly, lasts for a few weeks, and often repeatedly comes back.^[2] Scar formation does not typically occur.^[1]

Eosinophilic cellulitis
Other names	Wells' syndrome, recurrent granulomatous dermatitis with eosinophilia[1]
Initial rash in eosinophilic cellulitis
Specialty	Dermatology
Symptoms	Painful, red, raised, warm patches of skin, fever, joint pain[2]
Usual onset	Sudden and recurrent[2]
Duration	Few weeks[2]
Causes	Unknown[2]
Differential diagnosis	Vasculitis, cellulitis, anaphylaxis[2][1]
Medication	Corticosteroids, antihistamines[2][1]
Prognosis	Often goes away by itself[2]
Frequency	~200 documented cases[1]

Eosinophilic cellulitis is of unknown cause.^[2] It is suspected to be an autoimmune disorder.^[2] It may be triggered by bites from insects and arachnids such as spiders, fleas, or ticks, or from medications or surgery.^[2] Diagnosis is made after other potential cases are ruled out.^[1] Skin biopsy of the affected areas may show an increased number of eosinophils.^[2] Other conditions that may appear similar include cellulitis, contact dermatitis, and severe allergic reactions such as anaphylaxis.^[2]

Treatment is often with a corticosteroids.^[2] Steroids applied as a cream is generally recommended over the use of steroids by mouth.^[3] Antihistamines may be used to help with itchiness.^[1] Many times the condition goes away after a few weeks without treatment.^[2] The condition is uncommon.^[1] It affects both sexes with the same frequency.^[2] It was first described by George Crichton Wells in 1971.^[1][4]

Cause

Eosinophilic cellulitis is of unknown cause.^[2] It is suspected to be an autoimmune disorder.^[2] It may be triggered by bites from insects such as mosquitos,^[5] spiders, fleas, or ticks, or from medications or surgery.^[2]

Diagnosis

Histology of a skin biopsy from acute phase eosinophilic cellulitis. Note findings of plentiful tissue eosinophils and flame figures at the deeper corium sections (hematoxylin & eosin, original magnification ×40).

Diagnosis requires ruling out other potential causes.^[1] This includes ruling out vasculitis on skin biopsy.^[1]

Treatment

Treatment is often with a steroids.^[2] This can be either applied as a cream or taken by mouth.^[3] As the condition tends to get better on its own taking steroids by mouth should generally only be tried if the rash covers a large area and it does not get better with other measures.^[3]