Esophagitis is usually caused by acid reflux (GERD), infectious agents, or the adverse effects of medications. Infective esophagitis is most commonly observed in immunosuppressed hosts, but it has also been reported in healthy individuals. A wide range of abnormalities in host defense may predispose an individual to opportunistic infections, such as neutropenia, impaired chemotaxis and phagocytosis, alteration in humoral immunity, and impaired T-cell lymphocyte function. The prevalence of symptomatic infection is high in individuals with AIDS, leukemia, and lymphoma and very low in the general population.
Systemic illness and traumatic injury account for the remainder of causes. Patients with diabetes mellitus, adrenal dysfunction, alcoholism and those of advanced age can be predisposed to infectious esophagitis because of altered immune function. Illness that interferes with esophageal peristalsis, such as achalasia, progressive systemic sclerosis, and esophageal growths, may contribute to fungal esophagitis.
Steroids, cytotoxic agents, radiation, and immune modulators can also contribute to impaired host immune function. Disruption of mucosal protective barriers and antibiotics that suppress the normal bacterial flora may contribute to the invasive ability of normally harmless organisms. Steroid therapy contributes to fungal infection by suppressing both lymphocyte and granulocyte function, and medications can cause esophagitis by local or topical injury.