Reactivity of allergy skin test in healthy volunteers.
BACKGROUND
Healthy individuals may be exposed and sensitised to allergens, and have a positive response to a skin prick test despite being asymptomatic. The objectives of this study were to evaluate the prevalence of atopic sensitisation and identify the reactivity of healthy volunteers to common aeroallergens.


METHODS
Healthy volunteers with no known allergic symptoms were recruited in this study. All volunteers were scheduled to undergo a skin prick test with 16 common aeroallergens that were previously identified among atopic patients.


RESULTS
A total of 100 volunteers (mean age 28 years) were enrolled in this study. 42 volunteers had positive skin prick tests for at least one allergen. The median number of sensitised allergen was 2 (range 1-7). Volunteers with positive skin tests (n = 42) were younger than those with negative skin tests (n = 58) (mean age 25.5 vs. 29.2 years; p < 0.05). The group with positive skin tests also had a higher proportion of males (57.1% vs. 31.0%; p < 0.01) and first-degree relatives with a history of atopic diseases (31.0% vs. 10.3%; p < 0.05). The most common sensitised allergens in these healthy asymptomatic volunteers were mite (n = 33), house dust (n = 23) and American cockroach (n = 20).


CONCLUSIONS
In this study, up to 42% of healthy volunteers, particularly those with a family history of atopy, were sensitised to allergens. Reactivity of the skin test without allergic symptoms, however, does not indicate allergic disease. Therefore, the skin test should only be indicated in atopic symptomatic individuals.
Department of Medicine, Faculty of Medicine, Chulalongkorn University, 1873 Rama 4 Road, Patumwan District, Bangkok 10330, Thailand. hchantaphakul@gmail.com.
Phisit
P
Supakthanasiri
Jettanong
J
Klaewsongkram
Hiroshi
H
Chantaphakul
D000328:Adult; D000485:Allergens / Q000737:chemistry; D000818:Animals; D003058:Cockroaches; D003430:Cross-Sectional Studies; D003876:Dermatitis, Atopic / Q000175:diagnosis / Q000276:immunology; D004391:Dust; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D006967:Hypersensitivity / Q000175:diagnosis / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D008925:Mites; D012882:Skin Tests / Q000379:methods*; D055815:Young Adult
D000485:Allergens; D004391:Dust