Cat Scratch Disease: This is a common condition caused by Bartonella henselae, transmitted through cat scratches or bites, leading to painful lymphadenopathy, often in the axillary or neck region.

Infectious Mononucleosis: Caused by Epstein-Barr virus, it can lead to painful lymph nodes, especially in the neck, along with fever and sore throat.
Tuberculosis: Can cause painful lymphadenitis, particularly in the neck, and is more common in immunocompromised individuals or those exposed to TB.
Lymphadenitis due to Bacterial Infection: Bacteria like Staphylococcus aureus or Streptococcus pyogenes can cause acute lymphadenitis, which is painful and often accompanied by signs of infection like redness and warmth.

Lymphoma: Although less common, lymphoma (both Hodgkin and non-Hodgkin) can present with painful lymph nodes and is critical to diagnose early for effective treatment.
Metastatic Cancer: Certain cancers, like breast cancer, lung cancer, or melanoma, can metastasize to lymph nodes, causing them to become painful and enlarged.
HIV Infection: Acute HIV infection can cause painful lymphadenopathy as part of its initial presentation, along with fever, rash, and sore throat.

Kikuchi-Fujimoto Disease: A rare, self-limiting condition that causes lymphadenitis, typically in the neck, and is more common in young women.
Kimura Disease: A chronic inflammatory disorder that can cause painful lymphadenopathy and is often associated with eosinophilia and IgE elevation.
Castleman Disease: A rare disorder that involves an overgrowth of cells in the lymphatic system, leading to lymphadenopathy, which can be painful in some cases.