Idiopathic pulmonary fibrosis is a peripheral subpleural interstitial lung disorder limited to the lung not involving the airways. It has a poor prognosis (survival less than 5 years) and commonly an interstitial pneumonia radiological pattern. Patients complain of a chronic dry cough in 80% of cases. A cough is often the first symptom of this rare disease, preceding dyspnea by years, and is associated with a poor prognosis, high dyspnea scores and low FVC percentages. The pathogenetic mechanisms leading to coughing in IPF are unclear. This review focuses on recent evidence of cough pathophysiology in this disease. Gastroesophageal reflux may promote coughing in IPF patients; bile salts and pepsin may be abundant in BAL of these patients, inducing overproduction of TGF-β by airway epithelial cells and mesenchymal transition with fibroblast recruitment/activation and extracellular matrix deposition. Patients have an enhanced cough reflex to capsaicin and substance P with respect to control subjects. Moreover, patients with the MUC5B polymorphism show more severe coughing as MUC5B encodes for the dominant mucin in the honeycomb cysts of IPF patients. Comorbidities, including asthma, gastroesophageal reflux, hypersensitivity pneumonitis, bronchiectasis, chronic obstructive pulmonary disease and emphysema, can induce coughing in IPF patients. There is no clear explanation of the causes of coughing in IPF. Further research into the pathophysiology of IPF and the pathogenetic mechanisms of coughing is necessary to improve survival and quality of life.

Several drugs may have a number of adverse reactions (ADRs) involving the oro-facial region. The dose of the drug and the time required for the reaction to take place are relevant parameters; nonetheless, ADRs mechanisms are not always known and ADRs are not always predictable since aspects other than drug pharmacodynamics and/or pharmacokinetics, as well as various interacting variables contribute to the final outcome. All tissues and many functions of the oral cavity can be affected. In particular, salivary function is frequently involved and hypo-salivation is the main manifestation; several mucosal lesions with different morphology (ulcerations, vesiculobullous lesions, white lesions, pigmentations, swelling) are also possible. Taste, sensation and trigeminal function alterations have been reported and the recent evidence regarding the occurrence of jawbones osteonecrosis, especially in bisphosphonates treated patients, is increasing. Clinical management may be quite difficult due to the multiplicity of involved classes of drugs and substances (dental materials, foods), the variety of affected tissues and functions, the type of produced lesions and disturbances, the complexity of related pathogenetic mechanisms (if known), the difficulties in assessing causality and managing drug withdrawal and/or dose adjustment, as well as in establishing specific treatments, if any. In this paper the most common and significant oral ADRs, their related aspects and importance (including medico-legal implications) for health care providers will be discussed.