Objective Probiotics have proven beneficial in a number of immune-mediated and allergic diseases. Several human studies have evaluated the efficacy of probiotics in allergic rhinitis, however, evidence for their use has yet to be firmly established. The current systematic review seeks to synthesize the results of available randomized trials. Study Design Systematic review and meta-analysis. Methods The Medline, EMBASE, and Cochrane Library databases were reviewed and randomized controlled trials were extracted based on defined inclusion criteria. The effect of probiotics on Rhinitis Quality of Life (RQLQ) scores, Rhinitis Total Symptom Scores (RTSS), as well as total and antigen-specific serum IgE levels were evaluated by meta-analysis. Results A total of 23 studies with 1919 patients were identified, including 21 double-blind randomized controlled trials and 2 randomized crossover studies. Multiple probiotic strains, study populations, and outcome measures were utilized in individual trials. Seventeen studies showed a significant clinical benefit from the use of probiotics in at least one outcome measure when compared to placebo, while 6 trials showed no benefit. Among the trials eligible for meta-analysis, the use of probiotics resulted in significant improvement in RQLQ scores compared to placebo [standard mean difference (SMD) −2.23; p = 0.02]. Probiotics had no effect on RTSS [SMD −0.36; p = 0.13] or total IgE levels [SMD 0.01; p = 0.94], while there was a trend toward a reduction in antigen-specific IgE [SMD 0.20; p = 0.06] in the placebo group compared to probiotic. Conclusions Probiotics may be beneficial in improving symptoms and quality of life in patients with allergic rhinitis, however, current evidence remains limited due to study heterogeneity and variable outcome measures. Additional high-quality studies are needed to establish appropriate recommendations.

Letter to the Editor Probiotics in prevention and treatment of allergic rhinitis To the Editor, We read with great interest the article by Peng et al. 1 entitled, "The role of probiotics in prevention and treatment for patients with allergic rhinitis: A systematic review," which was published in July-August 2015. The effect of probiotics on chronic inflammatory disease has become a popular topic, with some positive findings in several studies. In their article, the authors systematically reviewed the literature for randomized controlled trials (RCT) that analyzed the use of probiotics for both the prevention and treatment of allergic rhinitis. Our group published a similar review earlier this year in the International Forum of Allergy and Rhinology entitled, "A systematic review and meta-analysis of probiotics for the treatment of allergic rhinitis." 2 We appreciate the authors' work because it is always useful to evaluate data from multiple perspectives; however, we would like to point out some differences in the two studies that may be of interest to both the journal readership and the general public. Systematic reviews have become an essential part of the medical literature, which allows for a thorough and unbiased analysis of published data. However, the way in which a systematic review is conducted can substantially alter data analysis and, ultimately, study conclusions. We noted that, in the study by Peng et al. 1 a total of six RCTs that analyzed the role of probiotics in allergic rhinitis treatment were identified and included for review. However, our study identified a total of 23 studies, including 21 RCTs and 2 crossover studies. 2 Despite a clearly described search algorithm and the use of similar databases, the reason for this discrepancy remains unclear. All studies not included by the authors were of fairly high quality, with a modified Jadad score of Ն3, and inclusion of these studies in our study resulted in analysis of Ͼ1900 patients, as opposed to the 306 reported by Peng et al. 1 We noted a lack of clear inclusion-exclusion criteria in the methods, and no limitations on date or year of publications was discussed. In addition, the article selection process did not include the reason for excluding articles at each step of the review, as is encouraged by standardized reporting guidelines. Similar to the conclusions by Peng et al., 1 our results were limited by study heterogeneity and the use of variable outcome measures, which thus prevented formal recommendations and highlighted the need for further study. However, the additional articles included for analysis did identify statistically significant differences in Rhinitis Quality of Life Questionnaire (RQLQ) symptom-specific outcome measures that were not identified by Peng et al. 1 In addition, the higher number of included studies certainly increases both the power and significance of the study results. We again thank the authors for their interesting study but wish for clarification regarding the mentioned discrepancies.

A 37-year-old gravida 5 para 4 with gestational hypertension underwent uneventful repeat cesarean delivery and tubal ligation under combined spinal-epidural anesthesia. On postoperative day 3, she developed a postural headache, unrelieved by caffeine, ibuprofen, and hydration. On postoperative day 8, she returned to the hospital for treatment. An epidural blood patch was administered, providing immediate and complete relief of her headache and bilateral upper and lower dental pain, which she noted arising concomitantly with her headache. We suspect bilateral traction on cranial nerve V2 and V3, secondary to intracranial hypotension after dural puncture, as the cause of her pain.