Study design, setting and participants
Children aged 2 to 17 who had admitted to the Pediatric Allergy and Asthma Unit of Gulhane School of Medicine with reactions after mosquito bites between 2015 and 2018 were enrolled in the study along with age and sex-matched control subjects who tolerated several mosquito bites without any unusual or large local reaction. Children in the control group had no history of physician-diagnosed allergic diseases and they admitted to our outpatient department for routine medical checkup.
Mosquito allergy was defined as large local reactions to mosquito bites consist of itchy, red, warm swellings appearing within minutes of the bites, and atypical reactions such as itchy papules, ecchymotic, vesiculated, blistering, bullous reactions, appearing in 6 hours after the bites and persisting for days or weeks (5). Demographic data, history of mosquito allergy (onset of the reaction, reaction type) and personal and familial history of other atopic diseases were recorded. Physical examination, morphology and other clinical manifestations of skin lesions were recorded. The skin reaction features of the children at the time of enrollment were classified into five stages due to the lifetime course of the process of sensitization and desensitization, as previously reported: stage 1, the bites cause no or little reaction (wheal < 4 mm, erythema < 4 mm or papule < 3 mm); stage 2, delayed reaction only (erythematous papules of > 4 mm develop 3–4 h after bite and with a peak at 24–36 h); stage 3, immediate reaction followed by delayed reaction (wheal of > 4 mm develops a peak ≤ 20 min after bite); stage 4, immediate reaction only; and stage 5, those with repeated bites eventually lose the reactions (2).
Asthma was defined as current symptoms (wheeze and cough) and positive bronchodilator responsiveness (improvement of FEV1 by 12% or more following administration of 200 mcg salbutamol), and/or a positive response to a trial of therapy with inhaled or oral corticosteroids (6). Allergic rhinitis was defined by the presence of rhinitis symptoms (rhinorrhea, nasal obstruction, nasal itching and sneezing), which are reversible spontaneously or with treatment in children with aeroallergen sensitization in the skin-prick test (7). Atopic dermatitis was defined as the presence of pruritus and a relapsing eczematous rash typically found over flexor surfaces (8).
The study was approved by the institutional review board of Gulhane School of Medicine and written informed consent was obtained from parents.
Study measurements