Allergic rhinitis is a common condition in adults and children and can have a large impact on patients' health and quality of life. The aim of current
allergic rhinitis therapies is to treat the subjective symptoms and to improve objective measures of the disease. Of the available treatment options for paediatric
allergic rhinitis, the newer oral
antihistamines and intranasal
corticosteroids are first-line treatments.First-generation
antihistamines are associated with unwanted adverse effects such as
cardiotoxicity, sedation and impairment of psychomotor function. Despite results from studies using first-generation
antihistamines demonstrating impairment of cognitive and academic function in children, many of these agents are still commonly given to patients. The newer
antihistamines, developed with the aim of being more specific for the
histamine H(1) receptor and of overcoming these adverse effects, are the medication of choice in patients with mild intermittent
allergic rhinitis. For children <12 years of age, three newer oral
antihistamines are currently available:
cetirizine,
loratadine and
fexofenadine. A lack of adverse effects with these
antihistamines has been demonstrated in children using EEG and psychomotor performance tests, and in clinical studies. However, issues of receptor selectivity and the potential for CNS adverse effects still remain, and further studies are warranted.Intranasal
corticosteroids are the most effective
anti-inflammatory agents used for the treatment of paediatric
allergic rhinitis; however, the safety of these compounds remains controversial. The safety implications associated with
corticosteroids are long-term, dose-related systemic effects, such as suppression of adrenocortical function, growth and bone metabolism, and the extent of these effects is influenced by a number of factors including
corticosteroid type, pharmacokinetic profile, mode of delivery and delivery device. Topical
corticosteroids were introduced to reduce the systemic effects seen with the long-term use of oral agents. The intranasal
corticosteroids currently available for the treatment of paediatric
allergic rhinitis -
beclometasone,
budesonide,
flunisolide,
fluticasone propionate,
mometasone and
triamcinolone - have short half-lives and rapid first-pass hepatic metabolism; however, their pharmacokinetics vary in terms of systemic absorption, potency, binding affinity, lipophilicity, volume of distribution, and half-life. A number of studies - utilising hypothalamic-pituitary-adrenal axis function tests such as plasma
cortisol levels, 24-hour urinary-free
cortisol tests; stimulation tests with
corticotropin (
adrenocorticotropic hormone),
lypressin, and
corticotropin-releasing hormone; and growth assessment studies using knemometry and stadiometry - have indicated that these intranasal
corticosteroids are well-tolerated in paediatric patients and do not significantly affect growth. The wealth of clinical data and the recommendations from evidence-based guidelines suggest that both
antihistamines and intranasal
corticosteroids have good safety profiles in children. Nevertheless, growth should be regularly monitored in children receiving intranasal
corticosteroids. Other treatments such as
immunotherapy, local
chromones and
decongestants can also be beneficial in managing paediatric
allergic rhinitis, and
therapies should be considered on an individual basis.