Wells syndrome

Evidence Levels: A Double-blind study B Clinical trial ≥ 20 subjects C Clinical trial < 20 subjects D Series ≥ 5 subjects E Anecdotal case reports

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Wells syndrome (eosinophilic cellulitis) is a rare inflammatory disorder resembling a bacterial cellulitis. Patients are often treated with antibiotics and fail to respond before the diagnosis of Wells syndrome is considered and then confirmed on skin biopsy. The pathogenesis remains obscure, but it is postulated that Wells syndrome represents a hypersensitivity reaction to a variety of stimuli, both endogenous and exogenous. Excessive production of interleukin-5 resulting in eosinophil accumulation and a local Th2 immune response have been documented. There are several recognized disease associations, including drug-induced disease. The condition can be recurrent, and although thought to be sporadic, familial patterns have been reported. The most common clinical manifestations are erythematous patches and plaques, but papulonodular and bullous types of Wells syndrome have been described. Characteristic histologic features include dermal edema with a marked eosinophilic infiltrate and flame figures (representing deposition of eosinophilic proteins and degradation products onto collagen fibers), although this is not specific to the condition. The usual course is of a pruritic sensation, followed rapidly by indurated, erythematous plaques of edema with violaceous edges that can form blisters. The lesions progress over a few days, resolving without scarring within 8 weeks. There is no anatomic predilection for plaques, and they may be solitary or multiple.