OBJECTIVES: To determine the prevalence and descriptive epidemiology of atopic dermatitis among school children in the general community in Singapore.
METHODS: This is a questionnaire study of 12 323 students done over a 1-year period, comprising 7 year olds (4605), 12 year olds (3940) and 16 year olds (3778) from 19 primary and 17 secondary schools randomly selected in Singapore. All children had a complete cutaneous examination. The diagnosis of atopic dermatitis was based on the U.K. Working Party diagnostic criteria. The questionnaire was translated into Chinese and both the English and Chinese versions were issued simultaneously to the students.
RESULTS: The 1-year period prevalence of atopic dermatitis was 20.8%. Atopic dermatitis was present in 22.7% of 7 year olds, 17.9% of 12 year olds and 21.5% of 16 year olds. The overall sex ratio was equal. There were slightly more boys with atopic dermatitis among the younger children (6 and 12 year olds, 1.18 : 1 and 1.19 : 1, respectively) but more girls were affected (1.57 : 1) among the 16 year olds. Atopic dermatitis was more common among the Chinese (21.6%) and Malays (19.8%) compared with the Indians (16%) and other races (14%). The onset of the disease occurred before the age of 10 years in 49.5% of the 16 year olds. "Pure" atopic dermatitis without concomitant respiratory allergies was noted in 788 respondents (30.7%); 1775 (69.3%) suffered from a "mixed" type, with 34.3% having allergic rhinitis, 9.5% having asthma and 25.5% having both asthma and allergic rhinitis. More boys had atopic dermatitis and concomitant respiratory allergies whereas more girls were affected with "pure" atopic dermatitis alone (1.4 : 1). At least one first-degree family member with atopy was noted in 1435 children (56%): atopic dermatitis (70%), asthma (62%) and allergic rhinitis (68%). Among siblings with one parent with atopic dermatitis, 37% had either a father or a mother with atopic dermatitis. Common aggravating factors reported included exercise, heat and sweating, grass intolerance, thick clothing and stress. Pityriasis alba was noted in 25% of the study population, keratosis pilaris in 13% and ichthyosis vulgaris in 8%. Most respondents had mild to moderate atopic dermatitis that could be controlled with a fairly simple regimen of moisturizers, topical steroids, antihistamines and antibiotics.
CONCLUSIONS: The high prevalence of atopic dermatitis in Singapore is similar to that observed in developed countries, suggesting that environmental factors may be important in determining the expression of the disease.
MATERIALS AND METHODS: In 2008, 142 newly diagnosed patients with AR were seen and underwent skin prick testing with 90 patients completing the study.
RESULTS: Intermittent mild and moderate/severe AR were evident in 10% and 21.1% of the patients, while persistent mild and moderate/severe were seen in 20% and 48.9%, respectively. Rhinitis and asthma co-morbidity occurred in 28.8% with asthma incidence significantly higher in persistent AR (P = 0.002). There was no significant association between AR severity, city living and asthma co-morbidity. Nasal itchiness and sneezing were the main presenting complaints and were more common in intermittent AR (P <0.05). Sleep disturbance was associated with moderate-severe AR (P <0.05). Polypoidal mucosa was associated with asthma co-morbidity (P <0.05). Monosensitivity reaction occurred in 12.2% of patients and was associated with fungi sensitivity (P <0.05). Majority of patients were oligosensitive (52.8%) and polysensitive (34.4%) and were significantly associated with moderate-severe persistent AR (P <0.01). The highest positive skin prick reaction and the largest average wheal diameter were for the house dust mites and cat allergen (P <0.05).
CONCLUSION: Our results reflected the AR profiles in our country, which was comparable with typical profiles of the neighbouring country and other Mediterranean countries with a similar temperate climate.