After initial clinical evaluation, a patient with sudden painful erythematous lesions on the face and neck was referred to dermatology. A suspected drug reaction led to discontinuation of the recent medication. A full workup was started, including biopsy, blood tests, antibodies, lupus anticoagulant, and serology, and oral corticosteroids were initiated.

Within 48 hours, lesions and pain improved significantly after corticosteroids. Laboratory findings showed leukocytosis with neutrophilia and presence of antibodies and lupus anticoagulant, while routine serology was negative. Twenty days later, biopsy confirmed Sweet syndrome.

Sweet syndrome is a rare inflammatory disorder. “Sweet syndrome, medically known as acute febrile neutrophilic dermatosis, is a rare dermatological condition categorized among the neutrophilic dermatoses.” It is defined by dense neutrophil infiltration in tissues and sudden painful erythematous papules or plaques that appear asymmetrically on the face, neck, upper trunk, and hands.

It is thought to be an immune-mediated hypersensitivity reaction driven by cytokines that recruit and activate neutrophils. Triggers include upper respiratory infections, paraneoplastic processes, and medications such as contraceptives, antibiotics, antiepileptics, antihypertensives, vaccines, and colony-stimulating factors. Drug-induced cases are more common in women. Because it may be linked to underlying malignancy, thorough evaluation is required to exclude systemic disease.

Diagnosis requires excluding mimicking conditions such as urticaria, contact dermatitis, toxicoderma, and cutaneous lupus through clinical, laboratory, and histopathology correlation. The condition responds rapidly to corticosteroids, with symptoms improving within hours and lesions resolving within a week. “The gold standard for initial treatment is the administration of oral corticosteroids.” In this case, biopsy and labs confirmed Sweet syndrome, ensuring targeted therapy.