TNF and ulcerative colitis: The elements known to be triggering factors include: arthropod bites (mosquitoes, fleas, ticks and spiders), cutaneous and/or systemic infections (Parvovirus B19, Herpes simplex viruses, Mumps virus, Toxocara canis and others), drugs (antibiotics, nonsteroidal anti-inflammatory drugs, vaccinations, anti-tumor necrosis factor [TNF]-α and other biologic drugs), haematological and solid organ malignancies and autoimmune diseases (Churg-Strauss syndrome and ulcerative colitis).