BACKGROUND: Over the last decades, the hypothesis that an allergic response could lead to the development of attention-deficit/hyperactivity disorder (ADHD) was raised and clinical studies investigated the co-existence of both. These studies had shown that allergic diseases and neurobehavioral disorders were concurrent and could be associated with genetic factors, neuroimmunity and microbial dysbiosis. To date, this was the first study in the Philippines to evaluate the prevalence and association of allergic diseases, its severity and ADHD symptoms.

OBJECTIVE: The objective of this study was to determine the association of allergic diseases and ADHD symptoms among children aged 6-12 years based on parental report using the Filipino version of the Vanderbilt ADHD Parent Rating Scale.

METHODS: School-aged children between 6 and 12 years with physician diagnosed allergies (bronchial asthma, allergic rhinitis, atopic dermatitis, allergic conjunctivitis, drug allergy, food allergy and/or acute or chronic urticaria) were randomly selected. Skin prick test (SPT) to aeroallergens was done. The parents completed the Filipino version of the Vanderbilt ADHD Diagnostic Parent Rating Scale (VADPRS), a screening tool for ADHD.

RESULTS: Among the 415 patients, 135 (32.5%) of them screened positive for ADHD symptoms. Upon assessment of the Vanderbilt parent rating subscale responses, 13.49% of the children were categorized as predominantly inattentive subtype, 6.02% as predominantly hyperactive/impulsive subtype and 13.01% as combined inattention/hyperactivity. Three hundred and seventy six (91%) children were diagnosed with asthma. Among these asthmatics, 119 (32%) had ADHD symptoms with the following subtypes - predominantly inattentive subtype (13.56%), predominantly hyperactive/impulsive subtype (5.05%) and combined inattention/hyperactivity (13.03%). Combined inattention/hyperactivity subtype had a significant proportion of severe asthmatics, as compared to mild or moderate asthma (p value = 0.026). Furthermore, 389 (94%) children were diagnosed with allergic rhinitis. Among these patients, 130 (33%) had ADHD symptoms with the following subtypes - predominantly inattentive subtype (13.62%), predominantly hyperactive/impulsive subtype (6.43%) and combined inattention/hyperactivity (13.37%). However, evidence was not sufficient to demonstrate an association between ADHD subtypes and allergic rhinitis severity. Lastly, 206 (50%) children were diagnosed with atopic dermatitis. Among these patients, 71 (34%) had ADHD symptoms with the following subtypes - predominantly inattentive subtype (14.56%), predominantly hyperactive/impulsive subtype (4.85%) and combined inattention/hyperactivity (15.05%). However, there was insufficient evidence to demonstrate a link between ADHD subtypes and atopic dermatitis severity.

CONCLUSION: Children with allergies, especially those with severe asthma, are more likely to have ADHD symptoms.