Position paper on olfactory dysfunction: 2023.

BACKGROUND: Since publication of the original Position Paper on Olfactory Dysfunction in 2017 (PPOD-17), the personal and societal burden of olfactory disorders has come sharply into focus through the lens of the COVID-19 pandemic. Clinicians, scientists and the public are now more aware of the importance of olfaction, and the impact of its dysfunction on quality of life, nutrition, social relationships and mental health. Accordingly, new basic, translational and clinical research has resulted in significant progress since the PPOD-17. In this updated document, we present and discuss currently available evidence for the diagnosis and management of olfactory dysfunction. Major updates to the current version include, amongst others: new recommendations on olfactory related terminology; new imaging recommendations; new sections on qualitative OD and COVID-19 OD; updated management section. Recommendations were agreed by all co-authors using a modified Delphi process. CONCLUSIONS: We have provided an overview of current evidence and expert-agreed recommendations for the definition, investigation, and management of OD. As for our original Position Paper, we hope that this updated document will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency, and generalisability of work in this field.

Complications to acute bacterial rhinosinusitis in children - a prospective study; bacterial cultures, virus detection, allergy sensitization and immunoglobulins.

BACKGROUND: Prospective studies of complications due to acute rhinosinusitis are lacking, bacterial cultures are hard to obtain and the role of airborne allergies, viruses and immunoglobulin levels are unclear. The aim was to investigate the role of bacteria, viruses, allergy and immunoglobulins in children hospitalized due to rhinosinusitis. METHODOLOGY: A prospective cohort study in Stockholm, Sweden, of children up to 18 years of age, hospitalized due to acute bacterial rhinosinusitis, from April 1st, 2017 to April 1st, 2020. RESULTS: Of 55 children included, 51% had a positive viral nasopharyngeal PCR and 29% had a positive allergy sensitization test. A higher percentage of middle meatus cultures were positive for bacterial growth compared to nasopharyngeal and displayed a wider array of bacteria. Dominating bacteria were S. milleri in surgical (7/12 cases), S. pyogenes in middle meatus (13/52 cases), and S. pyogenes and H. influenza in nasopharyngeal cultures (8/50 cases respectively). Nasal cultures were negative in 50% of surgical cases. An association was found between S. pyogenes and peak CRP; H. influenzae and peak CRP; S. pneumoniae and peak CRP; and possibly between M. catarrhalis and days of IV antibiotics. Further, an association between influenza A/B and S. pyogenes; a positive viral PCR and lower grade of complication and peak CRP; and a possible association between influenza virus and lower grade of complication. Allergy sensitization was possibly associated with a higher number of days with IV antibiotics. No immunoglobulin deficiencies were found. CONCLUSIONS: There seem to be differences in the patterns of bacterial growth in nasopharyngeal, middle meatus and surgical cultures in children with complications to acute bacterial rhinosinusitis. Presence of certain viruses and sensitization to airborne allergies seem to play a role in complications to acute bacterial rhinosinusitis in children.

Stathmin and EGFR correlates to HPV status and clinical outcome in sinonasal inverted papilloma.

BACKGROUND: Inverted papilloma (IP) is a locally destructive benign tumour of the sinonasal mucosa with a tendency for malignant transformation. Stathmin and epidermal growth factor receptor (EGFR) are important markers in cancer prognosis. Here we investigate if expression of stathmin and EGFR correlate to dysplasia, recurrence and HPV in IP. METHODS: 98 patients with IP diagnosed 2000-2010 were analyzed for stathmin and EGFR by immunohistochemistry (IHC) and HPV by polymerase chain reaction assay (PCR). RESULTS: All IPs expressed stathmin while its expression was absent or weak in normal mucosa. Dysplasia was present in 26,7% of IPs with high stathmin expression while only 7.4% of IPs with low stathmin expression showed dysplasia. Stathmin positive IPs showed a trend towards earlier recurrences. 57.1% of IP expressed EGFR but no significant association was seen between EGFR-positivity and recurrence or dysplasia. EGFR was expressed by 91.7% of the HPV-positive IPs compared to 52,3% of the HPV negative IPs. CONCLUSIONS: EGFR expression is significantly higher in HPV positive IP. Stathmin is expressed by all IP tumour cells. Stathmin was also associated with dysplasia and a trend towards a correlation between stathmin positivity and recurrence was found. Stathmin and EGFR might therefore be considered therapeutic targets.

Control of allergic rhinitis with MP-AzeFlu: a noninterventional study of a Swedish cohort.

BACKGROUND: The European Union has prioritised allergic rhinitis (AR) control. A visual analogue scale (VAS) has been endorsed as the AR control language and embedded into the most recent MACVIA-ARIA guideline. This study assessed the effectiveness and safety of MP-AzeFlu using a VAS in a real-life study in Sweden. METHODS: 431 patients aged 12 years or over with ARIA-defined moderate to severe AR were included in this multicentre, prospective, non-interventional study and prescribed MP-AzeFlu. Patients assessed symptom severity using a VAS from 0 (not at all bothersome) to 100 mm (very bothersome) on Days 0, 1, 3 and 7, and after approximately 14 days in the morning before using MP-AzeFlu. Patients' perceived level of disease control was assessed on Day 3. The proportion of patients who achieved a defined VAS score cutoff for well- and partly controlled AR was also calculated. RESULTS: MP-AzeFlu reduced mean (SD) VAS score from 67.9 (16.1) mm at baseline to 32.1 (22.8) mm on the last day. Results were consistent irrespective of severity, phenotype, patient age class or previous treatment. By Day 3, 84.0% of patients reported well- or partly controlled symptoms. Overall, 17.7%, 32.2%, 53.8% and 64.2% of patients achieved a 38 mm or greater "well-controlled" VAS score cutoff on Day 1, 3 and 7 and last day, respectively. CONCLUSIONS: MP-AzeFlu provided rapid, effective and sustained symptom control in patients with AR from Sweden in a realworld setting, aligning with EU and MACVIA-ARIA initiatives and supporting the effectiveness of MP-AzeFlu for AR treatment in real life.

Serious complications due to acute rhinosinusitis in children up to five years old in Stockholm, Sweden - Still a challenge in the pneumococcal conjugate vaccine era.

OBJECTIVES: The aim of this study was to analyze the rate of admissions, the rate of serious complications (postseptal orbital complications and surgery) and the bacterial etiology of acute rhinosinusitis in hospitalized children under five years old in Stockholm County, eight years after the introduction of the pneumococcal conjugate vaccine (PCV). The secondary aim was to compare this period with the period four years prior to the vaccine's introduction. METHODS: This was a population-based, descriptive observational study with retrospectively collected data from 1 July 2008 to 30 June 2016 in Stockholm County. Hospital admissions of children with a discharge diagnosis of rhinosinusitis and related complications were reviewed and compared to the pre-PCV period of 2003-2007. RESULTS: A total of 215 children were admitted, for a yearly incidence of 18.8 per 100 000 children (22.8 for boys, 14.6 for girls). Computer tomography-verified postseptal orbital complications occurred in 29 cases (13.5%) and surgery was necessary in nine (4.2%). Pathogens other than Streptococcus pneumoniae were found in the cases with postseptal complication or surgery (Streptococcus pyogenes in four, Haemophilus influenzae in three and Staphylococcus aureus in one case). In comparison to the four years pre-PCV, the incidence of admission decreased from 43.81 to 20.31 and 17.45 per 100 000/year for the two four-year periods after vaccine introduction. The incidence of CT-verified postseptal complication increased slightly from 1.51 to 2.34 and 2.74 per 100 000/year. The incidence of surgeries increased marginally but continued to be very low, from 0.22 to 0.54 and 1.03 per 100 000/year. CONCLUSIONS: Complications due to acute rhinosinusitis in children living in Stockholm County continues to be very rare after the introduction of pneumococcal vaccine. Hospitalization has decreased for children under five years old after PCV introduction, but the incidence or postseptal complications and surgery in the same population increased slightly. Predominantly bacteria other than Streptococcus pneumoniae was found. There is a need of larger studies to determine trends, and a need of prospective studies to elucidate the bacterial etiology, of serious complications due to acute rhinosinusitis in children.

Most preschool children hospitalised for acute rhinosinusitis had orbital complications, more common in the youngest and among boys.

AIM: This study established the incidence of acute rhinosinusitis and related orbital complications in tertiary care in Stockholm County and surveyed the clinical outcomes. METHODS: This was a population-based, retrospective, observational study, from July 1, 2003 to June 30, 2007, of the hospital admissions records of 213 children up to five years old, with a diagnosis of sinusitis and related complications. RESULTS: Preseptal cellulitis was present in 171 of the 213 admissions, which equated to an incidence of orbital complications due to acute rhinosinusitis of 36 per 100 000 people per year (95% confidence interval 26-49). Postseptal complications occurred in seven cases. The incidence rate ratio for hospitalisation of children less than two years old with rhinosinusitis compared with children aged 2-5 years was 2.8 (95% confidence interval 1.8-4.4). The incidence among boys was 53 per 100 000 people per year and 36 per 100 000 people per year for girls, and the incidence rate ratio was 1.5 (95% confidence interval 1.0-2.3). The most common bacterial finding was Streptococcus pneumoniae. CONCLUSION: Most children hospitalised for acute rhinosinusitis had an orbital complication, and this was more common in children under the age of two years and boys. Severe postseptal complications were rare.

Position paper on olfactory dysfunction.

Background: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate assessment techniques. Accordingly, effective treatments for smell loss are limited. In an effort to encourage high quality and comparable work in this field, among others, we propose the following ideas and recommendations. Whilst the full set of recommendations are outlined in the main document, points include the following: • Patients with suspected olfactory loss should undergo a full examination of the head and neck, including rigid nasal endoscopy with small diameter endoscopes. • Subjective olfactory assessment should not be undertaken in isolation, given its poor reliability. • Psychophysical assessment tools used in clinical and research settings should include reliable and validated tests of odour threshold, and/or one of odour identification or discrimination. • Comprehensive chemosensory assessment should include gustatory screening. • Smell training can be helpful in patients with olfactory loss of several aetiologies. Conclusions: We hope the current manuscript will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency and generalisability of work in this field.

Position paper on olfactory dysfunction.

BACKGROUND: Olfactory dysfunction is an increasingly recognised condition, associated with reduced quality of life and major health outcomes such as neurodegeneration and death. However, translational research in this field is limited by heterogeneity in methodological approach, including definitions of impairment, improvement and appropriate assessment techniques. Accordingly, effective treatments for smell loss are limited. In an effort to encourage high quality and comparable work in this field, among others, we propose the following ideas and recommendations. Whilst the full set of recommendations are outlined in the main document, points include the following: - Patients with suspected olfactory loss should undergo a full examination of the head and neck, including rigid nasal endoscopy with small diameter endoscopes. - Subjective olfactory assessment should not be undertaken in isolation, given its poor reliability. - Psychophysical assessment tools used in clinical and research settings should include reliable and validated tests of odour threshold, and/or one of odour identification or discrimination. - Comprehensive chemosensory assessment should include gustatory screening. - Smell training can be helpful in patients with olfactory loss of several aetiologies. CONCLUSIONS: We hope the current manuscript will encourage clinicians and researchers to adopt a common language, and in so doing, increase the methodological quality, consistency and generalisability of work in this field.

The link between parental allergy and offspring allergic and nonallergic rhinitis.

BACKGROUND: Parental allergy-related disease increases the risk for rhinitis, but it remains unknown how different phenotypes of parental allergy affect this risk. The aim of this study was to investigate how parental hay fever, asthma, and eczema affect the risk of allergic rhinitis (AR) and nonallergic rhinitis (NAR) at 8 years of age. METHODS: Information on 2413 children from a population-based birth cohort was used combining questionnaire data and IgE to inhalant allergens. Logistic regression was used to estimate the association between parental allergy-related disease and AR and NAR. In addition, cluster analysis was used to search for latent phenotypes of heredity likely to be associated with AR and NAR. RESULTS: At age 8 years, 13.8% of the children had AR, while 6.4% had NAR. Parental isolated hay fever increased the odds of AR (OR 2.2, 95% CI 1.6-3.2), whereas isolated asthma or eczema did not. The odds of NAR increased when one parent had two or more allergy-related diseases. In the cluster analysis, the highest proportion of AR, 37.5%, was seen in a cluster where both parents had hay fever and pollen allergy and that of NAR, 11.0%, in a cluster where one parent had hay fever, pollen allergy, and eczema. CONCLUSIONS: Parental allergy-related disease may be an important risk factor for NAR as well as AR, and the risk is comparable for maternal and paternal allergy. Parental hay fever seems to be the dominating hereditary risk factor for AR.

Chronic rhinosinusitis in asthma is a negative predictor of quality of life: results from the Swedish GA(2)LEN survey.

BACKGROUND: Asthma and chronic rhinosinusitis (CRS) both impair quality of life, but the quality-of-life impact of comorbid asthma and CRS is poorly known. The aim of this study was to evaluate the impact of CRS and other relevant factors on quality of life in asthmatic subjects. METHODS: This Swedish cohort (age 17-76 years) consists of 605 well-characterized asthmatics with and without CRS, 110 individuals with CRS only, and 226 controls and is part of the Global Allergy and Asthma European Network (GA(2) LEN) survey. The Mini Asthma Quality of Life Questionnaire (mAQLQ), the Euro Quality of Life (EQ-5D) health questionnaire, spirometry, skin prick test (SPT), exhaled nitric oxide (FeNO), smell test, and peak nasal inspiratory flow were used. RESULTS: Subjects having both asthma and CRS have lower mAQLQ scores in all domains (P < 0.001) and a lower EQ-5D index value and EQ-5D VAS value (P < 0.001) compared to those with asthma only. Asthmatics with CRS have significantly lower FEV1%pred and FVC%pred (88.4 [85.1-91.7] and 99.9 [96.7-103.0], respectively) compared with asthma only (91.9 [90.3-93.4] and 104.0 [102.5-105.5], respectively P < 0.05). Multiple regression analysis shows that low asthma quality of life is associated with having CRS (P < 0.0001), lower lung function (P = 0.008), current smoking (P = 0.01), BMI > 30 kg/m2 (P = 0.04), high age (P = 0.03), and a negative SPT (P = 0.04). CONCLUSIONS: Comorbid CRS was a significant and independent negative predictor of quality of life in asthmatics. Other negative factors were lower lung function, current smoking, obesity, advanced age, and having nonatopic asthma.

Quality of life is improved by endoscopic surgery and fluticasone in nasal polyposis with asthma.

BACKGROUND: The aim was to investigate the health impact of nasal polyposis with asthma and to study effects of endoscopic sinus surgery (ESS), and addition of fluticasone propionate nasal drops (FPND), on health related quality of life (HRQoL). METHODS: Prospective study of 68 patients with nasal polyposis and asthma. Effects were measured with Study 36-Item Short Form (SF-36). A randomized, double-blind, placebo-controlled 14-weeks phase measuring additive effects of FPND 400 µg twice daily (b.i.d.) was included. RESULTS: HRQoL was significantly decreased in both Physical Component Summary, PCS, (45 vs 48, p=0.049) and Mental Component Summary, MCS, (43 vs 51, p<0.001) vs reference population. ESS significantly improved PCS, (p=0.027) and MCS (p=0.021) after five weeks. We found significant additional benefit of FPND on three domains (RP, p=0.002; VT, p=0.007; SF, p=0.002). The increase in HRQoL with FPND reached reference population levels in all domains, as well as in both PCS (50, p=0.003) and MCS (52, p=0.002), five weeks after ESS. CONCLUSIONS: FPND 400 µg b.i.d. can be added to ESS in order to improve, and to reach population levels of, HRQoL already five weeks post-ESS. Physicians should evaluate HRQoL and consider ESS with nasal steroids early in their treatment of these patients.

Evaluation of nasal mucosal swelling and microcirculation throughout nasal and bronchial provocation tests with lysine-aspirin in asthmatics with nasal polyposis.

According to the GA2LEN recommendations, nasal challenge test with lysine-aspirin should be performed only in patients with severe asthma, because the sensitivity of this test has been lower than in bronchial and oral challenge tests. The AIA patient group often have severe asthma with impaired lung function, and therefore improvement of the nasal challenge is warranted. The outcomes of this study clearly indicate that a prolonged detection time from two to three hours might improve the sensitivity of the nasal challenge as a method for diagnosing aspirin intolerance. Moreover, we found a different vascular response in the nasal mucosa in the subjects with AIA after local challenge with lysine-aspirin as compared to an ATA patient group. This puts RSM-LDF as a possible new method in addition to those previously recommended for this particular test.

Genes regulating molecular and cellular functions in noninfectious nonallergic rhinitis.

BACKGROUND: Chronic noninfectious, nonallergic rhinitis (NINAR) is a complex syndrome with a principally unknown pathophysiology. New technology has made it possible to examine differentially expressed genes and according to network theory, genes connected by their function that might have key roles in the disease. METHODS: Connectivity analysis was used to identify NINAR key genes. mRNA was extracted from nasal biopsies from 12 NINAR patients and 12 healthy volunteers. Microarrays were performed using Affymetrix chips with 54 613 genes. Data were analysed with the Ingenuity Pathway System for organization of genes into annotated biological functions and, thereafter, linking genes into networks due to their connectivity. The regulation of key genes was confirmed with reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: In all, 43 genes were differentially expressed. The functional analysis showed that these genes were primarily involved in cellular movement, haematological system development and immune response. Merging these functions, 10 genes were found to be shared. Network analysis generated three networks and two of these 'shared genes' in key positions, c-fos and cell division cycle 42 (Cdc42). These genes were upregulated in both the array and the RT-PCR analysis. CONCLUSION: Ten genes were found to be of pathophysiological interest for NINAR and of these, c-fos and Cdc42 seemed to be of specific interest due to their ability to interact with other genes of interest within this context. Although the role of c-fos and Cdc42 in upper airway inflammation remains unknown, they might be used as potential disease markers.

Functional endoscopic sinus surgery improved asthma symptoms as well as PEFR and olfaction in patients with nasal polyposis.

BACKGROUND: Nasal polyposis is a disease known to be associated with asthma. The management is anti-inflammatory, with topical and oral corticosteroids as the first-line treatment. The effect of surgical treatment on lower airway inflammation has not been sufficiently studied. AIM: The aim of this study is to investigate the effects of functional endoscopic sinus surgery (FESS) as well as fluticasone proprionate nasal drops (FPND) 400 microg b.i.d. on nasal and lower airway parameters in asthmatics with nasal polyposis. METHODS: This was a prospective 21-week study of 68 patients with asthma and nasal polyposis, on the benefits of FESS on nasal '(butanol test, subjective olfaction, peak nasal inspiratory flow, congestion, rhinorrhoea, and polyp score)', and on the lower airway parameters (dyspnea, cough, mean daily peak expiratory flow rate (PEFR), and lung function tests). It also included a randomized, double-blind, placebo-controlled 14 weeks phase on FPND. RESULTS: Functional endoscopic sinus surgery significantly improved mean asthma symptom scores and daily PEFR and all nasal parameters including subjective and objective olfaction tests. This is the first study that shows the benefits of FESS on butanol tests in patients with nasal polyposis. We found no significant difference between topical treatment with FPND or placebo in the nasal or lower airway variables. CONCLUSION: Functional endoscopic sinus surgery improved nasal and asthma symptoms in patients with nasal polyposis. Functional endoscopic sinus surgery could be considered early in the natural course of nasal polyposis with concomitant asthma, as well as a second-line treatment in nasal polyposis patients with a reduced sense of smell. The potential benefits of FPND 400 microg b.i.d. were probably overshadowed by FESS.

A randomized controlled study evaluating medical treatment versus surgical treatment in addition to medical treatment of nasal polyposis.

BACKGROUND: Controlled prospective studies are needed to determine whether surgical treatment in fact has an effect additive to that of medical treatment of nasal polyposis. OBJECTIVE: We sought to compare the effect of medical treatment versus combined surgical and medical treatment on olfaction, polyp score, and symptoms in nasal polyposis. METHODS: Thirty-two patients with nasal polyposis and symmetrical nasal airways were randomized to unilateral endoscopic sinus surgery after pretreatment with oral prednisolone for 10 days and local nasal budesonide bilaterally for 1 month. Postoperatively, patients were given local nasal steroids (budesonide). Patients were evaluated with nasal endoscopy, symptom scores, and olfactory thresholds. They were followed for 12 months. RESULTS: The sense of smell was improved by the combination of local and oral steroids. Surgery had no additional effect. Symptom scores improved significantly with medical treatment alone, but surgery had additional beneficial effects on nasal obstruction and secretion. After surgery, the polyp score decreased significantly on the operated side but remained the same on the unoperated side. Twenty-five percent of the patients were willing to undergo an operation also on the unoperated side at the end of the study. CONCLUSIONS: Medical treatment seems to be sufficient to treat most symptoms of nasal polyposis. When hyposmia is the primary symptom, no additional benefit seems to be gained from surgical treatment. If nasal obstruction is the main problem after steroid treatment, surgical treatment is indicated. Selection of those who will benefit from surgery should be based on the patient's symptoms and not on the examiner's polyp score.

Pituitary adenylate cyclase-activating peptide 38 a potent endogenously produced dilator of human airways.

Pituitary adenylate cyclase-activating peptide (PACAP) 38 displays several biological activities relevant to obstructive airway disease. In this study, the occurrence of PACAP 38 in human small bronchi and corresponding pulmonary arteries was analysed immunocytochemically. The dilatory effects of this peptide on the same structures were also studied in vitro. A moderate number of PACAP-like immunoreactive nerve fibres was seen in association with bronchial and vascular smooth muscle and around seromucous glands. PACAP 38 caused a concentration-dependent relaxation of precontracted bronchial and pulmonary arterial segments. The maximal relaxation was more pronounced in the airways than in the arteries, whereas the potency in both was identical. PACAP 38 caused relaxation of all segments tested (nine patients), whereas vasoactive intestinal polypeptide (VIP) failed to cause relaxation of bronchial segments from six of nine patients. Both PACAP and VIP dilated all pulmonary arterial segments tested. In conclusion, pituitary adenylate cyclase-activating peptide 38 is a potent dilator of human bronchi and is present in the human lung. Pituitary adenylate cyclase-activating peptide 38 may, therefore, play a role in the endogenous regulation of airway tone. The inhibitory effects of pituitary adenylate cyclase-activating peptide 38 are more consistent than those of the related neuropeptide vasoactive intestinal polypeptide, perhaps reflecting a difference in susceptibility to degrading enzymes.

LTB(4)-induced nasal gland serous cell secretion mediated by neutrophil elastase.

Local allergen challenge causes nasal hypersecretion and also causes local leukotriene (LT) release, including LTB(4). Because LTB(4) causes leukocyte recruitment, and because neutrophil elastase is a potent secretagogue, we examined the hypothesis that LTB(4) causes nasal hypersecretion via neutrophil elastase. We developed a method for isolating and superfusing a nasal segment in dogs. Instillation of LTB(4) into the nasal segment caused a time-dependent increase in the volume of airway fluid, in lysozyme secretion, and in the recruitment of neutrophils. ICI 200,355, a selective inhibitor of neutrophil elastase, prevented LTB(4)-induced nasal secretion and lysozyme secretion, but it had no effect on neutrophil recruitment. We conclude that LTB(4) causes potent nasal secretion via release of elastase, and therefore LTB(4) may play a major role in allergic nasal hypersecretion.

Bronchodilatation in vivo by carbon monoxide, a cyclic GMP related messenger.

1. Recent studies suggest that gaseous carbon monoxide (CO) is involved in neurotransmission and that this molecule also is an important vasodilator in vivo. In the present study we evaluated the effect of inhaled CO on guinea-pig airway smooth muscle tone. The mechanisms involved were characterized by use of a cyclic GMP antagonist, Rp-8Br-cyclic GMPS, and a nitric oxide synthase inhibitor, L-NAME. 2. Anaesthetized, ventilated guinea-pigs were given a bolus injection of histamine (0.12 mg kg(-1), i.v.), followed by a continuous infusion of histamine (0.30 microg kg(-1) min(-1)) to increase total pulmonary resistance (RL). Subsequent exposure to 7, 15 or 30 breaths of CO (100%), resulted in a dose-dependent inhibition of the bronchoconstriction. In the highest dose tested (30 breaths), CO inhibited 80% of the histamine-induced increase in RL. 3. In separate experiments, animals receiving histamine infusions followed by 30 breaths of CO, were pretreated with Rp-8Br-cyclic GMPS (0.05 mg kg(-1)). This pretreatment abolished >60% of the CO-induced reduction in RL, but it had no effect on the bronchodilator response induced by salbutamol. In another set of experiments animals were pretreated with L-NAME (1.60 mg kg(-1)). In contrast to the Rp-8Br-cyclic GMPS pretreatment, the pretreatment with L-NAME did not affect the CO-induced reduction in RL. 4. The present findings indicate that CO causes bronchodilatation in vivo via cyclic GMP.

Capsaicin desensitization of the nasal mucosa reduces symptoms upon allergen challenge in patients with allergic rhinitis.

Patients with birch pollen allergic rhinitis were treated locally, out of season, in the nasal cavity with capsaicin (30 microM) or saline. The capsaicin treatment resulted in a statistically significant reduction of symptoms upon allergen challenge, which lasted for 2 months. Saline had no effect on the symptom score upon allergen challenge. Neither capsaicin nor saline treatment had any effect on allergen challenge-induced nasal mucosal swelling monitored by acoustic rhinometry. Allergen challenge-induced eosinophil migration to the nasal mucosa was affected by neither capsaicin nor the saline treatment. The finding that capsaicin treatment reduces allergic symptoms indicates that selective, non-peptide neurokinin receptor antagonists may be an alternative in the future in the treatment of nasal allergy. However, owing to the pain involved in local capsaicin treatment this treatment is unlikely to be of clinical use.