Allergy Workup in Allergic Rhinitis at Jeddah, Saudi Arabia

摘要

Background: Appropriate medical diagnosis and therapy of allergic rhinitis (AR) necessitate the identification of an IgE mediated sensitization to allergen. Objective: To explore the spectrum of allergy investigations in patients with AR. Settings: King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. Methods: This is a prospective cross-sectional study. 41 patients with symptoms and signs compatible with AR examined at ENT clinics were sequentially included. AR diagnosis was confirmed at Allergy clinic by a positive reaction to an in-vivo skin prick test (SPT) to common inhalant allergens (sensitization). AR cases then underwent different in-vitro tests: total peripheral eosinophil count (TPEC), total serum IgE, and specific IgE antibodies to common inhalant allergens by immuno-CAP system (Phadiatop). Results: AR confirmed by positive SPT was detected in 30 cases (73%). Their ages ranged between 16 – 52 years old (mean 27 ±9SD), and females constituted 60%. The predominant allergens were house dust mites (HDMs): Dermatophagoides pteronyssinus 70 % and D. farinae 67%, Cat 33%, Cockroach 33%, Salsola pestifer 23%, and Aspergilus 20%. TPEC ranged 10-1200 cell/mm3 (mean= SD), and eosinophilia (?450 cells/mm3) was found in 23%. Total IgE ranged 8 – 2000 IU/ml (mean= SD), and was elevated (>190 IU/ml) in 47%. Phadiatop was positive in 83% of AR cases. A very significant correlation between SPT and Phadiatop (df=1, P<0.001) was found. Conclusion: The prevalence of sensitization to inhalant allergens, particularly HDMs, by both in-vivo and in-vitro methods was common in AR cases at Jeddah. The presence of eosinophilia and/or high total IgE in the context of compatible clinical findings may help in the diagnosis of AR. This work advocates the importance of allergy workup for allergen sensitization in both AR diagnosis and the subsequent care of patients by promoting avoidance strategies. Introduction Allergic rhinitis (AR) is a common health problem for which many patients do not seek appropriate medical care (International 1994, Dywickz 1998, Fuad 2003). World wide, AR may affect 10-30% of the general population (Mygind 1996, Stracan 1997, Bousquet 2001). In a recent survey at Saudi Arabia, the prevalence of chronic rhinitis in children was found as high as 26%, and 62% of them were allergic based on positive skin prick test (SPT) (Sobki 2004). Although AR is not a life-threatening condition in most cases, it has a substantial impact on public health quality and the economy (Malone 1997, Weiss 2001, Sullivan 2001). Globally, these are on the rise today because of the increasing prevalence of allergic conditions and the higher cost of new medications (Tripathi 2001, Bousquet 2003, William 2004).AR is a symptomatic disorder of the nose induced by an immunoglobulin (IgE)-mediated inflammation of the nasal membranes in response to allergen exposure (King 1998, Druce 2003). Allergen exposures result in the bridging of 2 adjacent IgE molecules, leading to the release of preformed mediators from mast cell granules. These mediators (ie, histamine, leukotrienes, kinins) cause early-phase symptoms such as sneezing, rhinorrhea, and congestion. Late-phase reactions begin hours later and are caused by newly formed inflammatory cells (ie, eosinophils), which prolong the earlier reactions and lead to chronic inflammation.The diagnosis of AR is based on the clinical history, physical examination, and allergy workup is used mainly to confirm the presence of IgE mediated hypersensitivity (atopy) (Dykewicz 1998, King 1998, Shaikh 2004). Allergy workup includes a group of in-vitro and in-vivo tests. An elevated peripheral eosinophil count (eosinophilia) has been documented in some patients with AR, but it is less sensitive than nasal eosinophilia (Naclrio 1994, Druce2003, Shaikh 2004). Total serum IgE has been detected in as many as 30-60% of patients with AR (Hendrson 1971, Shaikh 2004). Antigen-specific IgE antibodies are the most important