Abstract

ITIKAWA, Ana; MALLOZI, Marcia C; WANDALSEN, Gustavo F  and  SOLE, Dirceu. Skin reactivity to inhalant allergens in allergic children and adolescents from a specialized outpatient clinic: Value of the skin index. Rev Port Imunoalergologia [online]. 2014, vol.22, n.4, pp.257-266. ISSN 0871-9721.

Rationale: Skin prick test (SPT) is an important tool in the evaluation of allergic sensitization and can be influenced by several factors. Skin index (ratio of allergen‑induced wheal diameter and corresponding histamine diameter; SI) have been used to improve the diagnostic power of SPT, especially in young children. Objective: To evaluate the SI in identifying allergic sensitization in patients followed at a specialized pediatric clinic. Material and methods: SPT of 1662 patients performed, between 2009 and 2014, to inhalant allergens, negative control (saline) and positive control (histamine, 1mg/mL) (IPI‑ASAC ® Brazil) were analyzed. Mean wheal diameters of allergens, histamine and negative control were recorded, according to different ages. All patients had a histamine positive SPT (wheal diameter equal or higher than 3 mm). Results: Skin reactivity to histamine increased significantly with increasing age. D. pteronyssinus and B. tropicalis were the predominant inhalant allergens identified. SI cut‑off points for the diagnosis of allergic sensitization were 0.6 for dust mites. However, when applying SI alone as the single diagnostic criteria for sensitization, we observe a reduction in the prevalence of sensitized patients. Conclusions: SI should be used in addition to SPT for the diagnosis of allergic sensitization in those patients who, despite of having low skin reactivity, had SI above 0.6 for D. pteronyssinus or B. tropicalis.

Keywords : Adolescents; allergic sensitization; children; histamine; inhalant allergens; skin index; skin prick tests.

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