Why does a fever accompany the sickle cell disease?

It doesn't always...: Patients with sickle cell disease can be immunocompromised because the disease causes the loss of your spleen, an important organ that helps the body fight certain infections. Fevers in patients with sickle cell disease are usually caused by infections. Fevers usually don't accompany pain crises.

Serious infection?: In sickle cell disease patients, fever can be an indication of severe infection where there is bacteria in the blood. This is a medical emergency. Failure to immediately seek medical attention for fever can result in sudden death for sickle cell patient. Not all fevers are serious infection; we can't tell at the start of the fever which are serious. Neither can the patient-see doctor when febrile.