Sézary syndrome (SS) is a rare, aggressive cutaneous T-cell lymphoma characterized by chronic erythroderma, pruritus, and systemic immunosuppression, leaving patients highly vulnerable to infections like COVID-19. The pandemic has intensified risks for SS patients, leading to severe outcomes such as acute respiratory distress syndrome (ARDS) and secondary infections. Immunosuppressive treatments for SS further complicate COVID-19 management, as they impair immune responses. The pandemic disrupted access to vital therapies, including chemotherapy, phototherapy, and clinical trials, while telemedicine proved insufficient for SS care, which requires physical examinations and blood tests. Vaccination remains crucial but presents challenges due to reduced efficacy in immunocompromised patients, necessitating additional vaccine doses and careful coordination with treatments. Psychosocial challenges, including isolation, anxiety, and interrupted support networks, further impacted SS patients. Lessons from the pandemic highlight the need for flexible healthcare delivery, improved vaccinations, and long-term monitoring of COVID-19’s effects. Future strategies should focus on tailored treatments and vaccines to ensure uninterrupted care for vulnerable populations during public health crises.