Table 1 Etiologic factors in erythema nodosum
From: Panniculitides of particular interest to the rheumatologist
| Infections | Pancreatic carcinoma |
| Streptococcal infections | Medications |
| Mycobacterium tuberculosis | Estrogens/oral contraceptive pills |
| Gastroenteritis due to Yersinia, Salmonella, and Campylobacter | Penicillin |
| Deep fungal infections: Blastomycosis, Histoplasmosis, Coccidioidomycosis, Sporotrichosis, Aspergillosis | Minocycline |
| Chlamydia pneumoniae | Sulfonamides |
| Chlamydia trachomatis | Halogens (bromides, iodides) |
| Mycoplasma pneumoniae infections | Salicylates |
| Cat-scratch disease | Chlorothiazides |
| Syphilis | Phenytoin |
| Infectious mononucleosis | Thalidomide |
| Herpes simplex | Underlying disease processes |
| Cytomegalovirus infections | Sarcoidosis (Lofgren’s syndrome) |
| Hepatitis B (infection or vaccine) | Crohn’s disease |
| Hepatitis C infection | Ulcerative colitis |
| Epstein–Barr virus | Behçet’s disease |
| Protozoal infections: Toxoplasmosis, Ancylostomiasis, Amebiasis, Giardiasis, Ascariasis | Sweet’s syndrome |
| Malignancy | Reiter’s syndrome |
| Hodgkin’s lymphoma | Takayasu’s arteritis |
| Acute myelogenous leukemia | Hormonal states |
| Carcinoid tumor | Pregnancy |