Background: Cytokine storm is a life-threatening immune reaction contributing to the severity of various infectious diseases such as COVID-19, sepsis, Ebola, and Dengue. Understanding its pathophysiology is critical for timely diagnosis and effective treatment. Methods: A narrative review was conducted using PubMed, Scopus, and Web of Science (September 2024 – January 2025). Keywords included “cytokine storm,” “pro-inflammatory cytokines,” “COVID-19,” “sepsis,” “targeted therapy,” and “personalised medicine.” Studies were analysed thematically. As a narrative review, the findings are limited by the heterogeneity and potential bias of included studies, and no quantitative synthesis was performed. Results: The review outlines key mechanisms of cytokine storm, such as IL-6, IL-10, and TNF-α overproduction, and presents clinical cutoff values (e.g., IL-6 > 19.5 pg/mL) associated with disease severity. Targeted therapies (e.g., tocilizumab, anakinra), immunomodulators (e.g., JAK inhibitors), stem cell therapy, and plasmapheresis were reviewed. A personalised approach to treatment based on biomarkers and comorbidities was emphasised. Conclusions: Cytokine storm remains a major challenge in infectious disease management. While therapeutic strategies are evolving, individualised, biomarker-driven treatment offers the greatest potential for improving outcomes