Skin test reactivity to indoor allergens correlates with asthma severity in jeddah, saudi arabia

Abstract

Background: There is increased emphasis on the role of indoor allergens in asthma.

Objective: To examine the spectrum of skin test reactivity (sensitization) to indoor allergens and its correlation with asthma severity in Jeddah, Saudi Arabia.

Methods: Asthmatic patients referred to the allergy clinic at King Abdulaziz University Hospital (KAUH) in Jeddah were studied. Measures of clinical severity were adopted from national and international asthma guidelines. The degree of sensitization was assessed by the wheal size (positive >/= 3 mm) from standard skin-prick tests for the following common indoor inhalant allergens: house dust mites (Dermatophagoides pteronyssinus [Dp] and Dermatophagoides farinae [Df]), cat, and cockroach.

Results: Skin test results from 113 of 151 (74.8%) asthmatic patients were positive for one or more allergens. The patients' ages ranged between 9 and 63 years (mean, 30 +/- 13 years), and females constituted 65.5%. The predominant asthma severity level was moderate persistent (55.8%), followed by mild persistent (33.6%). The prevalences of sensitization to indoor allergens were as follows: Dp, 87% (3-25 mm [mean, 7 mm]); Df, 84% (3-20 mm [mean, 7 mm]); cat, 44% (3-15 mm [mean, 6 mm]); and cockroach, 33% (3-12 mm [mean, 4 mm]). Higher asthma severity levels were significantly correlated with the number of allergens with positive sensitization (R = 0.3, p < .001) and with the degree of sensitization to house dust mites (Dp [degrees of freedom {df} = 16, p < .001] and Df [df = 17, p < .01]) but not to cat (df = 10, p < .24) or cockroach (df = 8, p < .36).

Conclusions: Immunoglobulin E-mediated skin test reactivity to indoor allergens, particularly to house dust mites, was common in asthmatic patients from Jeddah at KAUH. Increased sensitization was associated with higher levels of asthma severity, which is compatible with the literature. This emphasizes the importance of identifying sensitization to relevant indoor allergens in the clinical evaluation of asthmatic persons.

Figure 1

The degree of skin test reactivity (sensitization) to the indoor allergens studied. Wheal size was used as the measure of the degree of skin test reactivity (0-2 mm, negative; 3-5 mm, mild; 6-10 mm, moderate; >10 mm, severe).

Figure 2

Box plot of skin test reactivity to the different indoor allergens studied.

Figure 3

Mean skin test reactivity (wheal size in millimetres) to indoor allergens studied.

Figure 4

Number of allergens yielding sensitization, plotted against asthma severity.