Cutaneous lesions of hypereosinophilic syndrome (HES) may display various presentations. These are important to recognize to allow early diagnosis. We report an unusual case of a young man with HES secondary to a splenic T-cell lymphoma, revealed by diffuse necrotic cutaneous lesions. Later on, brain and heart infarctions developed, leading to the patient's death. Analysis of skin biopsy specimens showed occluded dermal vessels surrounded by activated eosinophils. Because a complete analysis of hemostasis was unremarkable, these findings suggest that dermal vessel thrombosis was the direct consequence of the migration of activated eosinophils. Cutaneous lesions of HES are protean and probably reflect the differences between the lesional events induced in situ by activated eosinophils.