Multiple chemical sensitivity (MCS) is an unexplained acquired medical condition that includes multiple, vague, recurrent, and non-specific symptoms in different organs. They are attributed to exposures to various and structurally unrelated environmental chemicals at concentration levels that are well tolerated by the majority of people and normally considered not to have toxic effects in humans. The aim of this review is to examine the multiple explanatory hypotheses for the pathophysiology of MCS: genetic, metabolic, neurological, immunological, and psychological. Several publications suggest a neurological and immunological activation. However, this neurological and immunological hyperresponse is not always observed when performing challenge tests. This suggests that behavioral conditioning could be an important mechanism in the pathogenesis of MCS. Even if psychiatric conditions appear not to be a major cause of MCS, in the case of genuine psychiatric disease, psychotherapeutic therapy is mandatory. Because of the complexity of the pathophysiology, there is no specific drug to treat MCS. However, the use of cognitive behavioral therapy is encouraged, as it has a significant positive impact on patients’ perception of their illness.

In recent decades, atopic diseases, such as atopic dermatitis (AD), allergic asthma (AA), allergic rhinitis (AR), and food allergy (FA) have been estimated rapidly increasing in prevalence. These diseases are characterized by the presence of specific immunoglobulin E (sIgE) and often relate to each other and develop in sequence (the so-called “atopic march”). AD may be the first early manifestation in infants followed by FA often within the first year of life. Moreover, AD is a risk factor for developing sensitization to airborne allergens later in life that can cause clinical manifestations of AA and AR. According to the dual-allergen exposure hypothesis, allergic sensitization to food allergens is promoted through cutaneous exposure, rather than the oral route. Moreover, there is evidence that exposure to food allergens, in particular peanuts, in the airway would also lead to food sensitization. The most frequent route of sensitization for inhalant allergens is still debated. Of note, a recent case report supports the development of sensitization to cat dander through a cat bite. Our review aims to provide an overview of current knowledge and unmet needs in the pathophysiology of respiratory and FAs.

Chronic rhinosinusitis (CRS) is a prevalent and burdensome condition worldwide, characterized by inflammation of the paranasal sinuses. Ideally, instead of treating CRS, we would identify ways to prevent the development of this chronic condition. Occupational exposures may be an excellent target for prevention. Occupational exposures have been shown to play a critical role in the pathogenesis of multiple lower airway diseases, such as asthma, silicosis, asbestosis, and hypersensitivity pneumonitis. However, evidence for the association between occupational exposures and the development of upper airway disease, like CRS, is less well-defined. This manuscript examines the association between occupational exposures and CRS. A scoping review of the literature following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines identified 19 relevant studies. The populations examined and the methods and criteria used for defining CRS diagnosis and occupational variables significantly varied between the studies. Diagnosis of CRS was most often determined by self-reported symptoms or medical record review. Occupational variables ranged from employment status to occupation type to specific exogenous compounds encountered. Overall, substantial evidence demonstrates a general association between occupational exposures and CRS diagnosis; however, limitations in study methodologies, including variations in CRS diagnostic criteria, occupational exposures, assessment methods, and populations, hinder drawing more specific conclusions. Moving forward, rigorous research methodologies and standardized criteria are essential to draw conclusions supported by multiple studies. Critical components of future studies should include large, diverse populations, use of consensus CRS diagnostic criteria, and inclusion of many specific and quantitatively defined exposures. Ultimately, such efforts can help inform preventative measures and interventions for CRS, thus mitigating the burden of CRS on individuals and populations worldwide.

As a novel respiratory viral infection, coronavirus disease 2019 (COVID-19) has influenced asthma in unpredictable ways. In the post-COVID era, there is a need to review asthma care and the new challenges and opportunities that are presented. Long COVID is a new and complex syndrome that has arisen. Treatable traits (TTs) have already been developed to address complex asthma and can be adapted to manage long COVID. Consumers are seeking more information on and answers to what to expect with a dual diagnosis of asthma and COVID-19. People with asthma identify a strong need for research into COVID and asthma. Completion of a national survey (n = 593) resulted in a list of research themes. From these, participants prioritized 10 asthma research themes. Among the top 10 asthma research priorities, the theme of COVID and asthma was ranked as the second priority in the overall rank list. Addressing these issues has the potential to improve global asthma health.