Photoinduced Classic Sweet Syndrome Presenting as Hemorrhagic Bullae
Sweet syndrome (SS) is characterized by fever; acute onset of painful erythematous papules, plaques, or nodules; peripheral neutrophilic leukocytosis; and histologic findings of a dense neutrophilic infiltrate without evidence of primary vasculitis. The authors report a rare case of classic SS presenting with hemorrhagic bullae over photoexposed areas. This case is notable because of the unusual nature of the clinical manifestation.
Bullous-type SS has been reported, but all the known cases were secondary to malignancy or were drug induced8,10; they did not present in a classic or idiopathic variant. Our case is unique in that it is a report of the classic SS variant with lesions including bullae over photoexposed areas, possibly indicating a causal association of sun exposure and the development of SS.
The diagnostic histopathologic features of SS include a dense, predominantly neutrophilic infiltrate located in the superficial dermis as well as prominent papillary dermal edema, which occasionally may lead to subepidermal vesiculation.11,12 The epidermis often is normal but spongiosis may be present, and rarely neutrophils may extend into the epidermis to form subcorneal pustules.13 Severe edema in the papillary dermis may cause subepidermal blistering and bullous lesions.10 Systemic steroids are the therapeutic mainstay in SS. Other treatment options include methylprednisolone, potassium iodide, colchicine, indomethacin, cyclosporine, and dapsone.
