Prevalence of asthma, rhinitis and eczema in children from the Bangkok area using the ISAAC (International Study for Asthma and Allergy in Children) questionnaires.

Within the past three decades, there has been a rising trend for prevalences of asthma and allergic diseases worldwide, particularly from developed and industrializing countries. In Thailand, limited studies on epidemiology of atopic diseases have indicated relatively low prevalences of these conditions among the Thais. Recently, a standardized phase I questionnaire of the International Study of Asthma and Allergies in Childhood (ISAAC) has been developed to study and to compare geographical and temporal trend for prevalences of asthma, allergic rhinitis and eczema in children. The objectives of phase I ISAAC study in Thailand are to study prevalence of the three most common allergic diseases i.e. asthma, allergic rhinitis and eczema among Thai children of the two age groups (i.e., 6-7 and 13-14 years) living in the Bangkok metropolitan area and to collect basic epidemiologic data of these diseases among these children. The Thai translated version of phase I ISAAC questionnaires was administered to Thai children of the two age groups as above. Questionnaires were answered by parents of younger children, whereas, they were self-administered by 13-14 years old children. In addition, the validated international video questionnaires were used with older children. Fourteen primary schools and 13 secondary schools were randomly selected to cover the entire Bangkok metropolitan area. A total of 7341 questionnaires were eligible for the analysis (3628 from the younger age group and 3713 from the older age group). Data were entered and analysed by the Epi-Info program. The cumulative and 12 month period prevalences of the three conditions for all children were as follows; wheezing, 18.3 per cent, 12.7 per cent; rhinitis, 44.2 per cent, 38.7 per cent; and eczema, 15.4 per cent, 14.0 per cent, respectively. The period prevalence of wheezing for older children (13.6%) was higher than for younger children (11.7%). Prevalences of severe wheeze and exercise wheeze were more common among older children (4.0% and 15.7%). Both age groups reported high percentages for night cough (23.6% and 28.6%). A significantly large number of children from both groups reported symptoms of rhinitis with the majority indicating that symptoms were severe enough to limit their daily activities. Nevertheless, when confined only to those with eye symptoms, the prevalence decreased to 13.1 per cent. Eczema, in contrast to the other two conditions, occurred more frequently among younger children than among older children (period prevalence of 16% vs 9.1%). The rash was of a relatively mild nature since 77 per cent of children reporting symptoms indicated that the rash had cleared within the past 12 months. Allergic conditions are very common among children residing in Bangkok. Compared to the last survey in 1990, the period prevalence of wheezing has increased 4 fold, allergic rhinitis has increased nearly 3 fold whereas, eczema has remained stable. A large number of children in Bangkok are suffering from rhinitis symptoms. Results of this phase I ISAAC study indicate that allergic diseases are perhaps the most common childhood diseases in Thailand and could lead to a substantial economical loss for the country. There is an urgent need for an in-depth study to define epidemiological factors responsible for this increase.

Theophylline pharmacokinetics in Thai children.

To validate a previously suggested dosing regimen of aminophylline administration for Thai children, we enrolled 13 asthmatic Thai children (5 girls and 8 boys) between the ages of 7.5-13.4 years (mean = 10.4 years) into a 36-hour, multiple-dose, oral theophylline pharmacokinetic study using plain aminophylline tablets at a dosage of 5 mg of theophylline base/kg every 8 hours. All patients were studied in the steady state. Blood samples were obtained every 2 hours for 24 hours; thereafter, samples were obtained more frequently for another 12 hours to determine theophylline pharmacokinetic parameters. Serum theophylline concentrations (STC) were assayed with a fluorescence polarization immunoassay method (TDX). Significant interpatient variations in STCs were observed. Five patients had peak STCs in the toxic range (> 20 micrograms/ml). Most patients had reproducible STC patterns during the study period; however, marked variations of STCs were observed with a mean percent of fluctuations [(Cmax-Cmin)/Cmin *100] of 535.6%. Using the PC Nonlin computer interpolation program by a modification with a baseline decay method and the Lagrange polynominal interpolation technique, approximate pharmacokinetic parameters were calculated and the results were as follows: plasma half life (t1/2) = 3.08 hours, elimination rate constant (Kel) = 0.26 hour-1, absorption rate constant (Ka) = 2.21 hour-1, volume of distribution (Vd) = 0.23 l/kg and plasma clearance (CI) = 56 ml/kg/hour. Since these calculated parameters could be imprecise due to delayed absorption of oral theophylline dosages, a single-dose intravenous theophylline pharmacokinetic study was further examined in another 18 patients (age range = 7-12 years, mean = 8.9 years) to determine more accurate pharmacokinetic data using intravenous aminophylline at dosage of 5.8 mg/kg.(ABSTRACT TRUNCATED AT 250 WORDS)

Nebulized salbutamol (Asmasal) in Thai children with asthma: comparison of three doses.

Eleven moderate-to-severe asthmatic children 5-11 years of age who were in stable condition were given (randomly, double-blind) nebulized salbutamol sulfate (Asmasal) inhalation therapy at doses of 0.1, 0.2 and 0.3 mg/kg body weight on separated days. All three doses of nebulized solution resulted in clinical improvement and improvement of lung function (FEV1, FVC, PEFR and FEF25-75%). A dose of 0.3 mg/kg produced greatest improvement and longest duration of improvement in FEV1 and PEFR, but the change was statistically significant only in PEFR at 60 minutes (p < 0.05). Five children experienced mild tremors. There were no significant changes in heart rate or blood pressure at any dose. It is concluded that a nebulized solution of salbutamol sulfate at a dose of 0.1-0.3 mg/kg is useful for treatment of asthma in Thai children, with very mild side effects.

Ice cube test in children with cold urticaria.

The ice cube test performed in 24 children (6 cold urticaria, 6 healthy, 6 allergic and 6 chronic urticaria) showed that a 3 and 5-minute ice cube test was the appropriate time for the diagnosis of cold urticaria without false positive results. If the test was prolonged to 10 and 20 minutes, 17% and 33% respectively showed false positive results in chronic urticaria other than cold urticaria patients. After four weeks of cyproheptadine therapy, the ice cube test showed only 17% positive at 3 minutes and 33% at 5 minutes. When the ice cube test was performed for 10 and 20 minutes, 67% showed positive results. In conclusion, the ice cube test should be performed for 3 to 5 minutes to diagnose cold urticaria in children. The time should be increased to 10 or 20 minutes if the test shows negative results at 3 to 5 minutes after antihistamine therapy.

Sinusitis in Thai asthmatic children.

The radiographic appearance of sinuses was studied in 146 Thai asthmatic patients aged 1-13 years. Forty-eight percent of cases showed sinusitis by the radiographic criteria. The maxillary sinus was most commonly involved (98.6%). Thirty-three percent had ethmoidal sinusitis and 7% of those with developed frontal sinuses had frontal sinusitis. Thirty-three percent had more than one sinus involved. Those with frontal sinusitis always had maxillary and/or ethmoidal involvement. Sixteen cases had signs and symptoms of sinusitis and all of the cases had the radiographic appearance of sinusitis. There was no correlation between the occurrence of sinusitis and duration or severity of asthma. There was no difference in the occurrence of sinusitis between those with or without allergic rhinitis. No correlation between severity of sinusitis and age of patients was observed.

The role of disodium cromoglycate-metered dose aerosol inhaler in the management of asthma in Thai children.

Metered dose aerosol inhaler of disodium cromoglycate (Intal) has been recently introduced to facilitate the ease of administration of the drug over its previous spincap formulation. We evaluated the efficacy of regular use of metered dose inhaler of disodium cromoglycate (DSCG-MDI) in the daily management of Thai asthmatic children. The study comprised nineteen children with the age range of 8-15 years (mean 11.6 years). During a two week baseline period, the patients recorded their baseline symptom scores, requirement of their asthma medications (medication scores) and their morning/evening peak flow (PEFR) readings. Thereafter, DSCG-MDI was prescribed at the dosage of two puffs (1 mg/puff) four times daily for eight weeks. Patients were examined at two week intervals at which daily score cards along with PEFR records were collected. Significant reduction in the medication scores and in the requirement for maintenance bronchodilators were noted (p less than 0.01) within two weeks of use of the DSCG-MDI. Morning and evening PEFR's increased significantly and this increase reached statistical significance at 4 weeks after the initiation of the treatment (p less than 0.01). No side effects were reported throughout the study; the aerosol was well tolerated. In this open study DSCG-MDI, at a dose of 1 mg four times daily, significantly improved asthma symptoms along with PEFR readings in Thai asthmatic children and reduced the need for concomitant asthma medications.

Wheat-induced anaphylaxis.

A 13 year old boy suffered two separate episodes of severe anaphylaxis after consuming sandwiches and a piece of bread. Prick skin testings with available food allergens only revealed a positive reaction to a 1:10 w/v of wheat flour extract. A diagnosis of wheat-induced anaphylaxis was made and a double blind food challenge was suggested however was declined by the family. The patient was instructed to avoid all wheat containing foods and to carry a kit containing an epinephrine pre-loaded syringe and an antihistamine tablet to be used in the event of inadvertant consumption with an instruction to seek medical assistance as soon as possible. Thus far, no further recurrence of anaphylaxis was encountered. A review of the current literature discloses that wheat-induced anaphylaxis is an uncommon event and could occur either immediately after the ingestion or with a concomitant exercise. The natural history of wheat allergy is currently not fully understood but may possibly be a life long event.