Hyperactivity and Impulsivity in Children and Allergic Rhinitis:
is there a link?
I-Ching Chou, MD
Department of Pediatrics, China Medical University Hospital, Taichung, Taiwan; Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan.
Address: No.2, Yuh-Der Road, North District, Taichung, Taiwan (Republic of China) (postcode: 40447)
TEL: +886-4-22052121 extension 4641 FAX: +886-4-22032798
Attention deficit hyperactivity disorder (ADHD) is the most common childhood neurodevelopmental disorder and substantially affects the social and behavioral development of children. Allergic rhinitis (AR) is the most common chronic condition in pediatric populations. Characteristic symptoms of AR can interrupt daily activities and disturb sleep, causing daytime inattention, irritability, and hyperactivity, which are also components of ADHD.
Recent evidence has suggested that sleep disturbance, poor school performance, and hyperactivity in AR children might be related to nasal allergies.1 In addition, an
increased prevalence and odds ratio of ADHD in AR patients was also observed in a study using the National Health Insurance Research Database (NHIRD) in Taiwan.2
However, the registries in the NHIRD claims primarily serve the purpose of administrative billing, and are not verified for scientific purposes. Contacting the patients directly to obtain further information is not possible because of the anonymity assured by scrambled identification numbers. Therefore, investigating inattention and hyperactivity in AR children by using objective and scientific measurements is required.
Yang et al investigated whether attention and impulsivity control in AR children differed from those of a control group.3 They used the AR symptom score, ADHD
attention and impulsivity of AR children, age-matched controls, and ADHD children. They observed that AR children scored higher in the ADHD symptoms questionnaire and made more commission errors in the CPT than did the control children.
Both AR and ADHD are highly heritable disorders; however, no known gene involving both AR and ADHD has been observed. The pathogenesis of the relationship between ADHD and AR remains unknown. First, immune and nervous systems exhibit delicate, complex, and dynamic interactions, in both healthy and diseased people.4 Mounting evidence has suggested that in addition to affording
communication between immune cells, specific cytokines play a role in signaling the brain to produce neurochemical, neuroendocrine, neuroimmune, and behavioral changes. Cytokines might act as neuromodulators and immunomodulators; the signaling might be part of a generalized and comprehensive mechanism to mobilize resources during physical and psychological stress as well as to maintain homeostasis.5 At the clinical level, advances in cytokine research have facilitated the
understanding of the pathophysiology of medical conditions and identification of novel treatments.6 These developments are particularly relevant to immune-related
disorders, such as infections, allergies, autoimmune diseases, and cancers. Second, other possible explanations for the association between AR and ADHD in previous reports have included shared symptoms, behavioral complications caused by annoying
AR symptoms, and associated sleep disturbances caused by AR, causing daytime fatigue, inattention, and impulsivity.7
Interpretations of the study presented several limitations. Children diagnosed with ADHD often suffer from concomitant psychopathologies, such as mood disorders, episodic outbursts, learning difficulties, sleep disturbance, and other behavioral problems. The clinical impact on affected patients is substantial, and patients presumably receive more attention in their care and pediatric visits, compared with control patients. The risk of controls developing allergic disorders might be underestimated because children suffering from minor allergic disorders might not visit pediatric clinics.
In conclusion, the study suggests that pediatricians caring for AR children should not only treat their allergies but also the possible comorbid impulsivity and inattention. In addition, in children exhibiting impulsivity and inattention, allergic diseases, particularly AR, should be considered in addition to ADHD. Although the precise mechanism remains largely unknown, evidence indicates that allergic diseases affect people diagnosed with ADHD. Additional large-scale longitudinal studies could provide definite answers to this crucial topic.
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2. Chou PH, Lin CC, Lin CH, Loh el-W, Chan CH, Lan TH. Prevalence of allergic
rhinitis in patients with attention-deficit/hyperactivity disorder: a population-based study. Eur Child Adolesc Psychiatry 2013; 22: 301-7.
3. Shyu CS, Lin HK, Lin CH, Fu LS. Prevalence of attention-deficit/hyperactivity 1disorder in patients with pediatric allergic disorders: a nationwide, population-based study. J Microbiol Immunol Infect 2012; 45: 237-42.
4. Yang MT, Lee WT, Liang JS, Lin YJ, Fu WM, Chen CC. Hyperactivity and
Impulsivity in Children with Untreated Allergic Rhinitis: Corroborated by Rating Scale and Continuous Performance Test. Pediatr Neonatol 2013;pii S1875-9572 : 00176-9.
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6. Kronfol Z, Remick DG. Cytokines and the brain: implications for clinical psychiatry. Am J Psychiatry 2000; 157: 683-94.
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