PIP: Although copper sulfate can cause systemic contact dermatitis, few such cases have been recorded among copper-releasing IUD users. Reported in this paper is a case of endometritis and urticaria-angioedema syndrome in a 32-year-old user of a copper IUD. Widespread urticaria, as well as angioedema of the eyelids and the labia majora and minora, persisted for about 6 months and were not responsive to corticosteroids and H1-antagonists. Copper sulfate positivity was demonstrated in 72-hour patch test, 48-hour application of the copper spiral to forearm, and in vitro lymphocyte-stimulating test. Histologic examination of the endometrial biopsy revealed vulvovaginitis with hyperplasia of the cervical canal and T-cell and eosinophilic granulocyte infiltration. Removal of the IUD caused complete symptom remission. In experimental animals with a radioactively labeled copper IUD, small amounts of copper sulfate are absorbed through the mucus membrane and carried to the cutis through the blood or lymph. In the cutis, the allergen is intercepted from antigen-presenting cells and recognized by T cells that migrate to the lymph nodes with blastic transformation, proliferation of cytotoxic lymphocytes, and cytokine production.