A Rare Case of Severe Neutropenia Due to Chikungunya Fever Which Improved With Filgrastim.

Chikungunya fever is a re-emerging viral illness affecting different parts of the world. Most patients recover without any serious complications. Here, we present a rare case of chikungunya fever with severe neutropenia and moderate thrombocytopenia. A 31-year-old male presented with a fever, body aches, and rash. Serial full blood counts revealed a very low neutrophil count (0.273 × 10/L) with a low platelet count (56 × 10/L). Dengue fever was excluded by doing both antigen and antibody tests. The IgM antibody against the chikungunya virus was positive. After giving one dose of granulocyte colony-stimulating factor (G-CSF) filgrastim, the neutropenia resolved. A few days later, the thrombocytopenia resolved as well. Other than episodic attacks of arthritis, he recovered completely. The absence of severe neutropenia and thrombocytopenia is considered a major demarcating feature between chikungunya fever and dengue fever. Cases like this one put physicians in a difficult position regarding accurate diagnosis and appropriate management plans. The use of filgrastim may be considered as rescue therapy in a situation like this.