Cat Scratch Disease: This condition, caused by Bartonella henselae, often presents with lymphadenopathy that can become necrotic, accompanied by high fever, especially after a cat scratch or bite. The lymph node involvement is typically unilateral and can be quite painful.

Tuberculosis (TB): TB can cause necrotic lymphadenitis, particularly in endemic areas or in individuals with compromised immune systems. The presentation can include high fever, night sweats, and significant lymph node enlargement that may become necrotic.
Lymphoma: Certain types of lymphoma, especially aggressive forms like diffuse large B-cell lymphoma, can present with rapidly enlarging lymph nodes that may undergo necrosis, accompanied by systemic symptoms such as high fever.
Bacterial Lymphadenitis: Bacterial infections, including Staphylococcus aureus or Streptococcus pyogenes, can cause lymphadenitis that progresses to necrosis, especially if not promptly treated. These infections are often associated with high fever and significant pain.

Malignant Histiocytosis: A rare but aggressive condition that can mimic lymphoma and cause necrotic lymphadenopathy with high fever. It's crucial to consider this diagnosis due to its poor prognosis and need for specific treatment.
Kikuchi-Fujimoto Disease: A self-limiting but potentially severe condition that can cause necrotic lymphadenitis, often accompanied by high fever and can be mistaken for more serious conditions like lymphoma.
Lymphogranuloma Venereum (LGV): Caused by certain serovars of Chlamydia trachomatis, LGV can lead to necrotic lymphadenopathy, especially in the context of genital infection. It's essential to consider this diagnosis, particularly in sexually active individuals, due to its implications for contact tracing and treatment.

Kimura Disease: A rare, chronic inflammatory disorder that can cause lymphadenopathy and eosinophilia, sometimes with necrosis, although it is more commonly associated with subcutaneous nodules and salivary gland enlargement.
Rosai-Dorfman Disease: A rare histiocytic disorder that can cause lymphadenopathy, which may rarely become necrotic, along with other systemic symptoms like fever. It's essential to consider this in the differential due to its unique treatment and prognosis.
Castleman Disease: A rare disorder that can cause lymphadenopathy, which may become necrotic in the unicentric form, often accompanied by systemic symptoms such as high fever. The multicentric form is more commonly associated with systemic symptoms and can be related to HIV infection or other immunocompromised states.