Introduction: During the COVID-19 pandemic, vitamin D was used along with vitamin C and zinc as a preventive and curative therapy against SARS-CoV-2 infection. Vitamin D toxicity, even if it is rare, occurs when serum concentrations exceed 150 ng/mL and is usually manifested by hypercalcemia phenomena. Case report: We hereby report a case of two twin sisters who self-medicated with vitamin D in a dose of 4 × 4,000 IU/day for almost 10 months as a method of ‘protection’ against COVID-19, influenced by mass media advertising. The patients presented to the emergency department with hypervitaminosis D-related symptoms such as hypertension, headache, nausea, vomiting, and diffuse abdominal pain. Laboratory investigations revealed high levels of vitamin D and calcium. Conclusions: Vitamin D toxicity can lead to difficulties in positive and differential diagnosis because of the multiple complications of hypercalcemia.

Introduction: Sweet syndrome, also called acute febrile neutrophilic dermatosis, is a rare disorder characterized by skin lesions accompanied by high fever and elevated inflammatory markers. Case Presentation: In January 2023, a 73-year-old Caucasian male was diagnosed with acute myeloblastic leukemia and subsequently chemotherapy with azacitidine and venetoclax was initiated. One week after the second round of chemotherapy with azacitidine, the patient developed a fever of 39˚C. Physical examination revealed purple plaques on the skin of the head, neck, and arms associated with pain but not itching. Initially, the plaques appeared at the site of the subcutaneous azacitidine injection (left upper extremity) and then began to spread. The infectious diseases consultation established the diagnosis of multiple abscesses. Antibiotic therapy was initiated with meropenemum and linezolidum, and later colistin was associated, but the skin lesions and the patient’s condition worsened. A dermatology consultation was performed, which established the diagnosis of Sweet syndrome, and subsequently corticosteroid therapy was started. The skin lesions started to improve after 3 days. Conclusions: Sweet syndrome is a rare condition that is difficult to diagnose because of the wide spectrum of differential diagnoses.