Incidence of grass and weed sensitization in Bangkok, Thailand: a clinical study

Background

Allergic rhinitis (AR) is a prevalent public health concern globally, significantly impacting quality of life. In Thailand, the prevalence of AR is rising, with grass and weed pollen identified as primary outdoor triggers.

Objectives

This study aimed to (1) assess patterns of pollen sensitization in Thai AR patients and (2) investigate correlations between demographics/clinical data and SPT results.

Methods

A total of 121 individuals aged ≥18 years with clinically diagnosed AR were recruited. Skin prick testing (SPT) was performed using a panel of commonly encountered tropical grass and weed pollen extracts. SPT wheal sizes and clinical symptom scores were recorded. Correlations between SPT outcomes and symptom scores were analyzed.

Results

Among the participants, 104 (85.95%) exhibited positive SPT reactions to at least one pollen type. Nutsedge (76/121), para grass (57/121), and Bermuda grass (48/121) were the most frequently identified allergens. Hurricane grass elicited the strongest reaction, evidenced by the highest average wheal size (6.2 mm). Poly-sensitization was observed in 77 (63.6%) of the SPT-positive individuals, with most cases involving two different pollen extracts (35/77). Notably, AR severity positively correlated with both average wheal size and the number of positive SPT tests.

Conclusion

This study highlights nutsedge, para grass, and Bermuda grass as major allergenic pollen sources for Thai AR patients. Including nutsedge, hurricane grass, and careless weed in clinical SPT panels is recommended for improved diagnostic accuracy. Additionally, the positive correlation between AR severity and pollen reaction strength emphasizes the importance of implementing patient education and avoidance strategies.

Nasal Cavity Length or Analyzed Nasal Segment of Acoustic Rhinometry in Thai Adults

Background

Nasal cavity length (NCL) is important for determining analyzed nasal segment (ANS) of acoustic rhinometry (AR). AR is a technique for nasal airway assessment which nasal cross-sectional areas and nasal volume (NV) are obtained. NCL or ANS is the important parameter to determine NV measured by AR. The ANS used to calculate NV in previous literatures vary from 4 to 8 cm. However, there has not been any study regarding NCL of Asians which is probably different from that of Western countries.

Objectives

To measure NCL in Thai adults using nasal telescope and compared NCL between left and right sides as well as male and female as well as among age groups.

Design

Prospective study.

Methods

This study was performed on patients, aged 18-95 years, who underwent nasal telescopy under local anesthesia at the Department of Otorhinolaryngology, Siriraj Hospital. Baseline characteristics (sex and age) of patients were collected. NCL (from anterior nasal spine to posterior edge of nasal septum) of both nasal cavities was measured using rigid nasal telescope of 0 degree. Mean NCL length of both nasal cavities was calculated.

Results

There were 1277 patients, with 498 (39%) male and 779 (61%) female. The mean ± standard deviation (SD) of NCL of male was 6 ± 0.6 cm whereas that of female was 5.7 ± 0.5 cm. There were no significant differences in NCL between left and right sides as well as among age groups in each gender (p > 0.05 all). However, male had significantly longer NCL compared with that of female (p < 0.001). The mean ± SD of NCL of total population was 5.9 ± 0.6 cm.

Conclusion

The NCL of Thais was approximately 6 cm. These data are useful to determine ANS used to calculate NV when AR is performed.

Plain Language Summaries

The length of nasal cavity (LNC) is important variable for acoustic rhinometry (AR) which is the instrument to measure nasal volume (NV). We use AR in clinical researches to diagnose and monitor the results of treatment of nose and sinus diseasesThe LNC used to calculate NV in previous studies vary from 4 to 8 cm. However, there has not been any study of LNC of Asians which is probably different from that of Western countriesWe measured LNC in 1277 Thai adults, aged 18-95 years, with 498 (39%) male and 779 (61%) female using nasal rigid endoscope and compared LNC between male and female.The average of LNC was 5.9 cm. Male had longer LNC compared with that female. The LNC of Thais was approximately 6 cm. These data are useful for AR to calculate NV.

Pattern of Aeroallergen Sensitization and Quality of Life in Adult Thai Patients With Allergic Rhinitis

The prevalence of allergic rhinitis (AR) is steadily rising in the Thai population, causing a major impact on the quality of life (QoL). Enhancing knowledge on common aeroallergens in the local setting helps in the appropriate prevention and management of AR. In this study, the demographic characteristics, clinical data, aeroallergen sensitization pattern, allergic symptoms, visual analog scale (VAS) score, and QoL are described. We evaluated the association between VAS, QoL, and severity of symptoms, except the aeroallergen sensitization pattern. We retrospectively reviewed the medical records of adult AR patients with a positive skin prick test (SPT) for at least one aeroallergen from January 2018 to May 2020. Standard descriptive and inferential statistics were used for analysis. A total of 366 patients were enrolled. Indoor aeroallergen sensitization and outdoor aeroallergen sensitization were observed in 32% and 7.9% of patients, respectively. Mono-sensitization was noted in 16.9% of patients, while poly-sensitization was noted in 83.1% of patients. Mites (65%) and sedge (39.3%) were the most common indoor and outdoor allergens. Nasal obstruction (74.6%), runny nose (63.7%), and nasal itchiness (61.5%) were the primary symptoms affecting the QoL. The association between VAS and symptom scores showed a trend of association with AR severity (Allergic Rhinitis and its Impact on Asthma [ARIA] classification) and VAS. AR has a significant effect on QoL in all domains of the validated generic (short-form-36, SF-36) and specific (rhino-conjunctivitis QoL questionnaire, Rcq-36) questionnaires. Mite and sedge remain the most common indoor and outdoor aeroallergens. The pattern of sensitization and number of aeroallergens were not associated with AR based on the ARIA guidelines. Meanwhile, symptoms of patients affected the QoL and VAS scores, which can be used as a quick and reliable tool for monitoring and stepping up or stepping down the treatment according to the next-generation guidelines. AR has a significant impact on the QoL of adult Thai patients.

Manila grass (Zoysia matrella) Zoy m 1 allergen may contribute to allergic sensitization in tropical/subtropical regions due to extensive cross-reactivity with other group-1 grass pollen allergens

BACKGROUND

Pollen of grasses in Chloridoideae and Panicoideae subfamilies is a major source of grass group-1 allergens in tropical/subtropical areas. Previously, most studies of subtropical grass pollen allergens have focused on Cynodon dactylon (Bermuda grass-Chloridoideae) and Sorghum halepense (Johnson grass-Panicoideae). However, little information is available about allergenicity of pollen from Zoysia matrella (Manila grass or Zoysia grass-Chloridoideae), which is among the most popular turfgrasses in tropical/subtropical areas.

OBJECTIVE

This study aimed to investigate the IgE reactivity and cross-reactivity of grass group-1 allergen from Z. matrella. In addition, the clinical relevance of Z. matrella in comparison with other species was assessed.

METHODS

IgE reactivity and cross-reactivity between recombinant proteins of group-1 allergen from Z. matrella (Zoy m 1) and C. dactylon (Cyn d 1) were determined by ELISA and immunoblot assays. Clinical relevance of Z. matrella pollen in Thai atopic patients was assessed using its pollen crude extract for skin-prick test, in comparison with extracts from four other pollen species.

RESULTS

The Zoy m 1 had high IgE binding and could interfere with binding to C. dactylon crude extract. In addition, Z. matrella pollen extract elicited positive skin-prick test results comparable to previously reported allergenic species. Group-1 grass pollen allergen was confirmed to be a major allergen from Z. matrella among Thai atopic patients and was officially designated Zoy m 1.0101.

CONCLUSIONS

Zoy m 1 allergen is a major allergen from Z. matrella that cross-reacts with other group-1 grass pollen allergens in the tropical/subtropical region.

Pattern of allergic sensitization in chronic rhinitis: A 19-year retrospective study

BACKGROUND

The pattern of allergic sensitization provides data for physicians to take appropriate care of allergic patients.

OBJECTIVE

To analyze the long-term pattern of allergen skin prick test (SPT) sensitization at a single tertiary care hospital in Thailand.

METHODS

Medical records of adult rhinitis patients during 1998 to 2017 were reviewed. Inclusion criteria were chronic rhinitis with positive SPT to at least one aeroallergen in the test panel. Outcome measures were SPT results, clinical symptoms, and their effect on patient quality of life (QoL). Descriptive statistics were used to demonstrate the pattern of sensitization. Multivariate linear regression was used to identify association between evaluated factors and patient QoL.

RESULTS

Six thousand five hundred and seventeen adult patients were included in this study. Mean age was 36.4 & 13.8 years. A majority of patients (59.4%) had positive SPT, and 83.7% of those had polysensitization. Dermatophagoides pteronyssinus and sedge were the most common indoor (54.8%) and outdoor allergens (37.7%), respectively. Compared among the various periods of data collection over a 19-year period, there was no major change in the pattern of sensitization. Considering the most recent data from 2013-2017, the prevalence of sensitization increased from 66.8% to 73.7% (p < 0.001). Clinical symptoms, except sneezing and allergen sensitization, affect QoL of chronic rhinitis patients (p < 0.001).

CONCLUSIONS

House dust mite and sedge are the most common indoor and outdoor allergens. There was no major change in the pattern of sensitization. Almost all allergic symptoms significantly affect QoL.