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.

Allergen skin test reactivities among asthmatic Thai children.

Skin prick tests with 14 selected local aeroallergens were performed on 100 asthmatic children aged 0-16 years attending the Pediatric Allergy Clinic, Faculty of Medicine, Siriraj Hospital. The 14 allergens included Dermatophagoides farinae, Dermatophagoides pteronyssinus, American cockroach (Periplaneta americana), Johnson grass (Sorghum halopense), Cladosporium clarosporoides, Alternaria tenuis, Penicillium mix, Aspergillus mix, cat dander, dog dander, milk, egg white, soy and shrimp. Positive skin test reactivity was defined as a mean wheal diameter > or = 3 mm at the 20 minute reading. There were 68 males and 32 females. Their ages were between 0-2 years (n = 1), 2-5 years (n = 19), 5-10 years (n = 49) and 10-16 years (n = 31). Of all the subjects, 22 were classified as having mild asthma, 74 with moderate asthma and 4 with severe asthma. At least one skin prick test was positive in 74 subjects (74%) and two positive tests in 66 subjects (66%). The prevalence of sensitization to various allergens was as follows; Dermatophagoides pteronyssinus 67%, Dermatophagoides farinae 62%, American cockroach 44%, shrimp 14%, Johnson grass 14%, cat dander 10%, Alternaria 7%, Cladosporium 7%, dog dander 5%, soy 4%, Penicillium 3%, Aspergillus 2%, milk 2% and egg white 1%. The wheal size to Dermatophagoides pteronyssinus did not correlate with age. In this group of asthmatic Thai children, house dust mites are the most important allergen causing sensitization.

A comparison of admission patterns of childhood asthma in 1982 and 1992.

The patterns of childhood asthma admission to the Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University in 1982 and 1992 were studied and compared. The number of childhood asthma admissions were 128 cases in 1982 an 132 cases in 1992. Male to female ratio changed from 1.3:1 in 1982 to 1.9:1 in 1992. The average age on admission was 57 months in 1982 vs 62 months in 1992 which was not significantly different (p > 0.05). The admission pattern of cases under 1 year of age went down from 16% in 1982 to 6% in 1992. At emergency room, adrenaline injection was used for all asthma cases in 1982 but decreased to 30% of the patients in 1992 with the replacement of nebulized beta 2 agonist. The percentage of cases that were treated with aminophylline, corticosteroid and oxygen therapy were comparable between both periods. The most common form of steroid used in admissions changed from hydrocortisone in 1982 to methyl prednisolone in 1992. The use of antibiotics went down from 92% in 1982 to 80% in 1992. All of the admission cases in both periods recovered and were later discharged. The average period of admission was 3.9 days in 1982 and was not significant different (p > 0.05) from 4.9 days in 1992.

Cold urticaria in Thai children: comparison between cyproheptadine and ketotifen in the treatment.

The study was performed in 6 Thai children with primary acquired cold urticaria. They all suffered from generalized urticaria and two of them also had angioedema. All of them had normal erythrocyte sedimentation rate, complement 3 and negative VDRL, TPHA, hepatitis B screen and cold agglutinin titer. Cryoglobulin was checked in 3 cases and showed negative results A double-blind cross-over study to compare the effectiveness of cyproheptadine and ketotifen demonstrated that the efficacy of cyproheptadine and ketotifen on clinical symptoms and ice cube test was not significantly different (p > 0.05). Both of them showed good results in the treatment of cold urticaria with mild side effects. During the follow up, 5 cases showed complete recovery while the other one developed one or two exacerbations per year upon cold exposure. However, the symptoms were mild and subsided on administration of one or two doses of H1 antihistamine. Our data demonstrated that ketotifen was as effective as cyproheptadine in the treatment of cold urticaria in Thai children.

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.

Clinical evaluation of the "Siriraj Spacer" in asthmatic Thai children.

We designed a new, washable, and collapsible bag spacer (the Siriraj Spacer) for use with metered-dose inhalers (MDI) by Thai asthmatic patients. The Siriraj Spacer consists of a mouthpiece, a front panel to which any type of MDI could be attached and a collapsible 800 mL ringed-plastic bag. Fifteen asthmatic children (6-13 years of age) were enrolled into a randomized, double-blind, triple crossover study (spanning a period of three days) to compare the clinical effectiveness of the Siriraj Spacer with that of the Volumatic Spacer (Glaxo, Inc., Research Triangle Park, NC, U.S.A.) and with the use of MDI alone. Medication used with the active method of administration was 2 puffs of albuterol (100 micrograms/puff) while 2 puffs from placebo MDI were used with the other two methods in succession. All children were stable asthmatic patients, and had been instructed how to use MDI properly by an open mouth technique just before the initiation of the study. Spirometry (FEV1, FVC, PEFR, and FEF25-75%) was followed for six hours after the administration of albuterol. The baseline FEV1s of the three study days were within 50% to 70% of the predicted values (with baseline variability of less than 20%). Data were expressed as percentage of improvement from baseline. By an analysis of variance with repeated measures, no significant differences were observed between pulmonary function data obtained with any of the three methods of bronchodilator administration (P > .05) at any time point throughout the 6-hour period.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Suppressive effects of histamine skin reactivity by a nonsedating antihistamine-mequitazine.

The suppressive activity of mequitazine (MQZ) on histamine skin reactivity was evaluated in 29 healthy subjects (age 22-25 years) in a single-blind study. Fifteen subjects received MQZ, at a dosage of 5 mg BID, for 7 days while 14 served as controls. A prick skin test with saline or histamine hydrochloride (1 mg/ml and 10 mg/ml) was performed in duplicate, on both forearms, starting from the baseline day and continuing for 4 days after medication had been discontinued (total of 11 days). The skin-test subject and the reader was unaware of the randomization process. Mean diameters of wheal and flare as well as the skin index scores (after Voorhost) were used in the analysis. Maximal flare suppression (as compared to the baseline values) was observed on day 6 (97% suppression for 1 mg/ml and 54% suppression for 10 mg/ml, p less than 0.01). Suppression of wheal size was significant (19% for 1 mg/ml and 28% for 10 mg/ml) but was not clinically relevant. Suppression of skin index scores was maximal on day 6 (71% for 1 mg/ml and 43% for 10 mg/ml, p less than 0.01). After MQZ had been discontinued, all measurements gradually returned to baseline values and were not different therefrom within 3 days. However, final measurements of wheal and flare were smaller than baseline values (60-94% of baselines). We conclude that MQZ, at the manufacturers's recommended dose of 5 mg BID, significantly suppressed flare size of histamine skin tests and recommend that MQZ be discontinued for at least 3 days prior to performing allergy skin tests.

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.

Childhood asthma in Thailand.

Asthma is common in Thai children with a prevalence of about 4%. A prospective study of 2,000 Thai asthmatic children showed boys to be more frequently affected than girls, and fifty percent of patients experienced their first attack within the first 2 years of life. Attacks usually occurred in winter and the rainy season. 63.15% of patients had asthma associated with other allergic diseases and 79.25% had a family history of allergic diseases. Positive skin tests to important antigens were noted in 93.7% of cases, and house dust was the most common. Pharmacokinetic studies of theophylline were made in Thai asthmatic children after oral administration revealed that the elimination half-life of theophylline was longer than that observed in subjects in Western countries. Long-term follow up of 247 Thai asthmatic children revealed that in 37.2% of patients, symptoms ceased at the age of 15 years. The factors which indicated a favorable prognosis included male sex, mild or moderate illness, negative skin tests or positive skin tests to only a few allergens.

Pharmacokinetics of oral theophylline in Thai asthmatic children.

Pharmacokinetic studies of theophylline were carried out in 12 Thai asthmatic children after oral administration of Elixir Quibron and Tablet Aminophylline. No significant differences in any of the pharmacokinetic parameters between these two dosage forms were observed. Peak serum concentrations of theophylline were reached in an average time of 3.16 hours (range 1.71-7.71). It was shown that the elimination half-life of theophylline in Thai asthmatic children (average 7.21 hours) was longer than that observed for subjects in western countries. Variations in elimination half-lives ranging from 4.44 to 14.34 hours were intersubject variations. Due to the slow elimination of theophylline in Thai patients, a dosage regimen of 5 mg/kg every 8 hours was recommended as more suitable than 5 mg/kg every 6 hours. Using data from this study, the predicted maximum and minimum serum theophylline concentrations at steady state were calculated to be 16.53 micrograms/ml and 9.96 micrograms/ml, respectively. This dosage regimen should be suitable not only for Thai people but also for Asian people of similar races and under similar environmental conditions.

Asthma in Thai children: a study of 2000 cases.

Two thousand Thai children with asthma were studied prospectively. Boys were more frequently affected than girls, with the ratio of 1.54:1. Fifty percent of patients developed their first attacks within the first 2 years of life. Attacks during the night were common and the seasons in which attacks usually occurred were the winter and the rainy season. Viral respiratory infections were the most common precipitant of attacks. The majority of the cases (61.25%) were moderately severe, while 29.15% of cases were mild and 9.60% of cases were very severe. Among our patients, 32.45% had been hospitalized with asthma and 6.85% had received corticosteroid treatment for asthma. In this study, 63.15% of cases had asthma associated with other allergic diseases, and 79.25% had family history of allergic diseases. Absolute blood eosinophil counts of less than 500 cells/mm3 were found in 39.8% of patients. Positive skin tests to important antigens were noted in 93.7% of cases, and these were house dust, epidermals, house dust mite, molds, weeds, cockroach, grasses, kapok, and foods.

Protective value of BCG vaccination in children in Bangkok, Thailand.

The protective effect of bacille Calmette-Guérin (BCG) vaccination against tuberculosis is controversial. In a study, 330 patients less than 12 years of age with tuberculosis, 52.1% of whom had had BCG vaccination, were compared with a control group of 1106 patients free of tuberculosis, 81% of whom had BCG vaccination. The occurrence of disseminated forms of tuberculosis, tuberculous meningitis, tuberculous peritonitis, and tuberculosis of bone and joints in BCG-vaccinated patients was quite low. With BCG vaccination, the incidence of the disseminated form of tuberculosis was significantly lower than that of pulmonary tuberculosis with pulmonary parenchymal lesions, primary pulmonary complexes, and pleural effusion. Tuberculous peritonitis was significantly less frequent than pulmonary tuberculosis with pulmonary parenchymal lesions, enlarged hilar glands, pulmonary primary complex, and pleural effusions. The study demonstrated that BCG gave an overall protective effect of 74% and that a major effect of this immunity was to produce a localized form of tuberculosis.

Urticaria in Thai children.

In this study, 142 patients under 12 years of age with the diagnosis of urticaria accompanied or not by angioedema were examined. In all 72.6% of the patients were under 6 years of age. Boys and girls were equally affected, 13.4% of the cases had chronic urticaria, 56.3% had a previous history of urticaria, 88.0% had generalized urticaria, and about half of the cases had associated angioedema. The causes of the urticaria were identified or suspected in 32.4% of the cases. Drugs, foods, insect bites and stings, infections and cold were the most common or associated precipitating agents in that order. Histories revealed 27.5% of the cases had records of other allergic diseases, and 76.1% had allergic diseases in the family. Dermographisms were found in 16.2% of the cases, and 22.5% of cases had eosinophilia. The means of IgE levels in both acute and chronic urticaria were within normal limits, and there was no statistically significant difference between the two groups. Skin testing was of little practical value in evaluating the etiology of the urticaria. Clinical trials of drugs for symptomatic treatment revealed that clemastine, ketotifen and hydroxyzine gave approximately equally high response rates. All these three medications gave significantly greater response rates than chlorpheniramine.