Thermal water inhalation for allergic rhinitis and recurrent respiratory infections: a narrative review of the evidence

Allergic rhinitis (AR) and recurrent respiratory infections (RRIs) are common conditions that significantly impact quality of life and healthcare systems. Thermal water inhalation therapies have emerged as a potential non-pharmacological option due to their immunomodulatory and anti-inflammatory properties. This narrative review aimed to evaluate the efficacy and safety of thermal water inhalations in managing patients with AR and RRIs. The inclusion criteria were pertinent articles written in English and published in journals listed in PubMed. Six studies conducted in Italy, involving 548 participants (most of whom were children and adolescents), met the inclusion criteria. Significant improvements were observed in nasal mucociliary transport time, with reductions ranging from 2 to 8 min across treatment groups. Total Symptom Scores decreased significantly (one study reported a > 50% reduction). The frequency and duration of upper respiratory tract infections were reduced considerably in the treatment groups compared to the controls. However, results for nasal cytology were inconsistent, and heterogeneity in study designs limited comparability. The reviewed studies highlighted the potential of thermal water therapies to enhance mucociliary clearance, alleviate symptoms, and reduce reliance on other pharmacological treatments. On the other hand, these studies have a regional limitation and this review was not systematic. In conclusion, this narrative review may suggest that thermal water inhalations could be a promising option for managing patients with AR and RRIs, providing an alternative therapy with significant clinical benefits. Nevertheless, further high-quality, standardized, and international studies are necessary to confirm these findings and facilitate meta-analyses. These treatments could play a valuable role in reducing the burden of respiratory and allergic conditions.