Infections:
Viral syndrome
Infectious mononucleosis
Cat scratch disease
HIV
Tuberculosis, atypical mycobacteria
Infections (detailed):
Localized (a response to a local cutaneous infection, e.g. staph or strep) vs. Generalized (a response to a systemic infection. e.g. see bacterial, viral, parasitic, and fungal)
-Viral syndrome: adenovirus, cytomegalovirus, hepatitis, herpes zoster, HIV, infectious mononucleosis (Epstein-Barr virus), rubella
-Bacterial: Brucellosis, leptospirosis, cat-scratch disease (Bartonella), chancroid, lymphogranuloma venereum, primary and secondary syphilis, tuberculosis, atypical mycobacteria, tularemia, typhoid fever, Lyme disease
-Parasites: Toxoplasmosis, helminthic, rickettsial, scrub typhus
-Fungal infection: coccidioidomycosis, cryptococcosis, histoplasmosis
Neoplasm: Malignancy
Diffuse involvement: E.g. lymphomas and leukemias
Diffuse invasion: E.g. metastatic disease, Kaposi sarcoma,
Localized invasion: E.g. a head and neck tumor; skin cancers.
Non-neoplastic
Giant lymph node hyperplasia (Castleman disease)
Histiocytosis
Histiocytic necrotizing lymphadenitis
Kimura disease
Drugs: Meds that can cause lymphadenopathy include: Trimethoprim/sulfamethoxazole, Allopurinol, Atenolol, Captopril, Carbamazepine, Hydralazine, Penicillins, Phenytoin, Primidone, Pyrimethamine, Quinidine, Sulindac
Vessels: Kawasaki disease.
Autoimmune: Dermatomyositis, rheumatoid arthritis, Sjögren syndrome, Still disease, systemic lupus erythematosus, sarcoidosis, amyloidosis.
Iatrogenic: serum sickness.
Enviromental (occupational): berylliosis, silicosis.
Thinking through the Differential diagnosis
The entire differential diagnosis for Lymphadenopathy can be divided into two groups: Generalized vs. Localized causes.
VINDICATED MEN mnemonic helps with remembering the major mechanisms of disease in each group.
Further Reading
Michael Karpf, Chapter 149: Lymphadenopathy, in “Clinical Methods: The History, Physical, and Laboratory Examinations.” 3rd edition. https://www.ncbi.nlm.nih.gov/books/NBK256/
Iran J Med Sci. 2014 Mar; 39(2 Suppl): 158–170. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3993046/
Am Fam Physician. 2016 Dec 1;94(11):896-903. https://www.aafp.org/afp/2016/1201/p896.html