👉 Splenitis is a condition in which the immune system mistakenly attacks and inflames the spleen, causing inflammation of the spleen. This can lead to symptoms such as fever, fatigue, jaundice (yellowing of the skin), abdominal pain, nausea, and weight loss. Spleenitis is usually caused by an infection with bacteria, viruses, or parasites that target the spleen's immune system. It can also be caused by autoimmune disorders like lupus, rheumatoid arthritis