Sweet’s syndrome (SS) is a neutrophilic dermatosis characterised by the acute painful erythematous plaques or nodules accompanying fever and leukocytosis with neutrophilia. Although the etiology has not been elucidated clearly, many reports support the association of SS with abnormal conditions such as infections, malignancy and drugs. However, trauma has been rarely reported to cause this disease, which is known as the pathergy phenomenon. A 69-year old woman underwent surgical ligation and stripping for varicose vein on her right leg. After the surgery, she was consulted to our department for skin change on her right leg with fever. The physical examination revealed localized erythematous swollen patch with plaque on the right upper thigh. The laboratory results showed neutrophilia with elevated C-reactive protein and erythrocyte sedimentation rate. The skin biopsy result was consistent with SS. Ten years ago, she had radical hysterectomy and bilateral lymphadenectomy followed by adjuvant radiotherapy for cervical cancer. We report a case of localized SS after varicose vein surgery who had a past history of radical hysterectomy with lymph node dissection and radiation therapy. Although rare, trauma can be a trigger for SS. Furthermore, most of the post-operative skin reaction may be reminiscent of infections, but SS should be included in the differential diagnosis though post-operative skin infection is suspected.