Otitis media (OM), an infection in the space behind the ear drum, is one of the most common childhood infectious diseases worldwide. More than 70% of all children have at least one middle ear infection by the age of six years. Approximately 5-10% of patients turn to chronic OM which eventually causes hearing loss and sequelae. The pathogenesis of chronic and/or recurrent OM is multifactorial, including genetic predisposition, dysfunction of the Eustachian tube, impairment of the mucociliary system, hyperproduction of mucins, metaplasia/hyperplasia of mucous cells, and active secretion of ions and water. However, the detailed disease mechanisms for OM remain elusive. For example, we know that genetic predisposition is one of the factors leading to OM but it is not clear which genetic backgrounds play a role in OM. Again, mucous cell metaplasia is unclear at the moment although tremendous efforts and endeavors have been made in the recent years. It is believed that multiple factors (bacterial infections/metabolites, inflammatory cytokines/chemokines, and genetic/epigenetic changes) are involved in this cardinal change of middle ear mucosa. Mucous cell metaplasia is frequently associated with mucous cell hyperplasia (thus termed mucous cell metaplasia/hyperplasia). Mucous cell metaplasia/hyperplasia tends to drive OM into a chronic status, associated with abundant production of mucins in the diseased middle ear mucosa. This leads to an OM entity, that is, OM with mucoid effusion. The main focus of this special issue will be the pathogenesis of OM with mucoid effusion, including disease mechanisms through which acute infections in the middle ear turn into chronic infections or recurrent infections; molecular mechanisms through which mucins and effusions are produced; cellular events through which mucous cells are induced from general epithelial stem cells in the middle ear mucosa; bacterial metabolites/inflammatory cytokines that modulate the development of mucous cells in the middle ear; transcription factors and other molecules that are responsible for differentiation of mucous cells in the middle ear; possible factors that increase the risks for mucous cell metaplasia/hyperplasia, in addition to signal pathways that trigger submucosal fibrotic disorders; inductive signals for development of cholesteatoma under chronic OM conditions; genetic background through which patients are predisposed to chronic OM; clinical strategies for diagnosis of chronic OM using new technologies. Potential topics include, but are not limited to:

• Mucins and mucin regulation in middle ear epithelial cells
• Mucous cell hyperplasia/metaplasia in OM
• Pathogenic mechanisms of OM predisposition
• Fibrotic disorders in chronic OM
• Signaling pathways in OM
• New approaches and technologies for diagnosis of chronic OM
• Mouse otitis media models
• Genetics and OM susceptibility
• Cholesteatoma and chronic OM

Before submission authors should carefully read over the journal's Author Guidelines, which are located at http://www.hindawi.com/journals/ijol/guidelines/. Prospective authors should submit an electronic copy of their complete manuscript through the journal Manuscript Tracking System at http://mts.hindawi.com/ according to the following timetable: