Abstract
INTRODUCTION: Rabies is a zoonosis caused by viruses of the family Rhabdoviridae. Prophylaxis with the rabies vaccine and immunoglobulins, depending on the severity of the case, is recommended. After vaccination, mild, moderate, or severe adverse events (AE) are described. Although rare, severe skin reactions may occur, increasing the risk of anaphylaxis. CASE REPORT: An 84-year-old woman was attacked by a stray unknown cat, leaving her with bites and scratches in the neck region and multiple injuries. The case was classified as severe. About 3 h after the first dose of the rabies vaccine, disseminated purplish spots appeared on her lower limbs, worsening significantly after the second dose, requiring hospitalization for the application of the third dose under observation, dermatology evaluation, and collection of skin tissue for biopsy. She was discharged 24 h after the third vaccination, and the purple spots cleared gradually. The biopsy suggested an adverse reaction to the vaccine components. Immunohistochemistry of the rabies virus antigen in dermal nerve fillets was negative. The seroconversion post rabies vaccine showed IgG antibody values below the reference levels. CONCLUSION: Vaccination against rabies is extremely important; however, AEs may occur. Our patient developed an important AE and required hospitalization. After complete vaccination, the serum was not converted. A similar case was not previously described, and the case report is important for the creation of jurisprudence on rabies vaccination in elderly patients in Brazil.