Background: Acute upper respiratory tract infections (URTIs), including the common cold and rhinosinusitis, are common afflictions that cause discomfort and debilitation and contribute significantly to workplace absenteeism. Treatment is generally by antipyretic and decongestant drugs and sometimes antibiotics, even though most infections are viral. Nasal irrigation with saline is often employed as an adjunct treatment for URTI symptoms despite a relative lack of evidence for benefit in this clinical setting. This review is an update of the Cochrane review by Kassel et al, which found that saline was probably effective in reducing the severity of some symptoms associated with acute URTIs.

Objectives: To assess the effects of saline nasal irrigation for treating the symptoms of acute URTIs.

Search methods: We searched CENTRAL (2014, Issue 7), MEDLINE (1966 to July week 5, 2014), EMBASE (1974 to August 2014), CINAHL (1982 to August 2014), AMED (1985 to August 2014) and LILACS (1982 to August 2014).

Selection criteria: Randomised controlled trials (RCTs) comparing topical nasal saline treatment to other interventions in adults and children with clinically diagnosed acute URTIs.

Data collection and analysis: Two review authors (DK, BM) independently assessed trial quality with the Cochrane 'Risk of bias' tool and extracted data. We analysed all data using the Cochrane Review Manager software. Due to the large variability of outcome measures only a small number of outcomes could be pooled for statistical analysis.

Main results: We identified five RCTs that randomised 544 children (three studies) and 205 adults (exclusively from two studies). They all compared saline irrigation to routine care or other nose sprays, rather than placebo. We included two new trials in this update, which did not contribute data of sufficient size or quality to materially change the original findings. Most trials were small and we judged them to be of low quality, contributing to an unclear risk of bias. Most outcome measures differed greatly between included studies and therefore could not be pooled. Most results showed no difference between nasal saline treatment and control. However, one larger trial, conducted with children, did show a significant reduction in nasal secretion score (mean difference (MD) -0.31, 95% confidence interval (CI) -0.48 to -0.14) and nasal breathing (obstruction) score (MD -0.33, 95% CI -0.47 to -0.19) in the saline group. However, a MD of -0.33 on a four-point symptom scale may have minimal clinical significance. The trial also showed a significant reduction in the use of decongestant medication by the saline group. Minor nasal discomfort and/or irritation was the only side effect reported by a minority of participants.

Authors' conclusions: Nasal saline irrigation possibly has benefits for relieving the symptoms of acute URTIs. However, the included trials were generally too small and had a high risk of bias, reducing confidence in the evidence supporting this. Future trials should involve larger numbers of participants and report standardised and clinically meaningful outcome measures.