Allergen sensitization to aeroallergens including Blomia tropicalis among adult and childhood asthmatics in Thailand.

To study prevalence of allergen sensitization among asthmatics in Thailand, skin prick tests (SPT) were performed in 84 pediatric, 71 adult asthmatics and 71 adult volunteers. Allergen extracts used for testing included common allergens in Thailand and in Singapore. The incidence of positive SPT to any allergen among the three groups (childhood, adult patients and adult controls) were 64.3%, 43.7% and 35.2%, respectively. Dermatophagoides were the most common allergens sensitized by both pediatric (58.3%) and adult asthmatics (40.8%). Twenty-four children (28.6%) and 8 adult patients (11.3%) were sensitized to storage mites (Blomia tropicalis and/or Austroglyciphagus malaysiensis). All patients sensitized to Blomia tropicalis were sensitized to Dermatophagoides. Twenty-seven percent and 15.5% of childhood and adult asthmatics were sensitized to cockroach allergens. The rates of sensitization to oil palm pollen in childhood and adult asthmatics were 8.3% and 5.6%, respectively. Sensitization to other pollens and spores were less than 5%. This study confirms the importance of Dermatophagoides among Thai asthmatics.

Vacuum cleaning does not sufficiently reduce mite allergens from beddings.

INTRODUCTION: Conflicting results exist with regard to the efficacy of vacuum cleaners on the removal of mite allergens from bedding. OBJECTIVES: The authors prospectively compared a short term efficacy of two types of regular vacuum cleaners (National-N and Hoover-H) with a specialized cleaner (Vorwerk-V) in the removal of mite allergens from mattresses. MATERIAL AND METHOD: Thirty-five dormitory beds with high mite allergen concentrations at the baseline period (month 0) were selected. They were matched into three groups according to group I mite allergen concentrations (N 11 beds, H 12 beds, V 12 beds). Vacuuming was performed on months 1 and 4 by the assigned vacuum cleaner in each group. Immediately after, mattresses were vacuumed by a reference cleaner (another National vacuum cleaner) at both months. Vacuuming was performed over the entire bed for 2 minutes/square meter. Group I mite allergens (sums of Der p 1 and Der f 1) were measured; concentrations and total mite allergens removed by the tested cleaners as well as by the reference cleaner, at various time points, were compared. RESULTS: Ability to remove mite allergens by vacuum cleaners depends on weight of dust removed and also on mite concentrations in the dust samples. Despite the fact that H and V appeared to remove higher mite allergens than N, such differences were not statistically significant (p > 0.05), both at month 1, and 4. Surprisingly, mattress mite concentrations removed by both high capacity cleaner groups (V & H) increased at month 4, whereas, it remained unchanged in the third group (N). This increase led to a concomitant increase in total allergen removed by V and H. Nevertheless, remaining total allergens in the mattresses in V and H, as judged from the amount of allergens obtained by the reference cleaner, increased at month 1 and 4 compared to baseline values (p < 0.05), whereas, no change was observed in N. CONCLUSION: Although high capacity vacuum cleaners removed a large amount of mite allergens from mattresses, they did not sufficiently reduce mattress mite allergen burden as determined by the reference cleaner during this short term study.